CSC 379:Week 4, Group 4

2007-07-28T14:43:58Z

Becreswe: /* What are Biometrics? */

CSC 379:Week 4, Group 4

2007-07-28T14:35:48Z

Becreswe: /* Biometrics and Privacy of Genetic Data */

CSC 379:Week 2, Group 1

2007-07-15T07:35:11Z

Becreswe: /* Ethical considerations of international usage */

=Creative Commons=

==Overview==

===Provisions of Creative Commons License===

Based upon copyright protections, the various forms of the creative commons licenses allow the creator of a work to declare "some rights reserved" instead of the usual "all rights reserved" associated with plain copyright. This allows the creator of the original work to grant certain permissions to those who wish to use the original work without the prospective user having to explicitly ask for permission.

There are 4 conditions that make up the different Creative Commons licenses:
;Attribution: All Creative Commons licenses require attribution as specified by the original work's creator when the work is used, distributed, or modified whether in its original form or as a derivative work.
;Noncommercial: The original work may only be used, distributed, or modified only for noncommercial purposes whether the work is in its original form or as a derivative work.
;No derivative works: The original work may be used or distributed, but may not be used in any form of derivative work.
;Share alike: Derivative works based upon the original work may only be distributed under an identical license to the original work.

These conditions are combined in various forms to make the six main Creative Commons licenses:
# Attribution (by)
# Attribution Non-commerical (by-nc)
# Attribution Non-commercial Share Alike (by-nc-sa)
# Attribution Non-commercial No Derivatives (by-nc-nd)
# Attribution No Derivatives (by-nd)
# Attribution Share Alike (by-sa)

'''Links'''
*[http://creativecommons.org/ Creative Commons]
*[http://creativecommons.org/about/licenses/meet-the-licenses Creative Commons Licenses]
*[http://wiki.creativecommons.org/FAQ Creative Commons FAQ]

===Comparison to other common licenses===

{| border="1" cellspacing="0" cellpadding="2"
! License
! Advantages
! Disadvantages
! Ethical Considerations
|-valign="top"
|Creative Commons
|
*Creator of work can grant specific permissions for re-use of work
*Rights and conditions of others to use work are more clearly laid out
*Based on copyright
|
*Must be careful to choose appropriate license to retain the desired amount of control over the work
*Must specifically designate work as licensed under Creative Commons
*Users of Creative Commons-licensed works must be careful when combining works with different licenses
|
*There is a disclaimer of warranty that the individual granting the license has the right to do so
*Certain provisions of the license change between countries
|-valign="top"
|Copyright
|
*Automatically granted to created works, even without notice
*Reserves all rights for the creator
|
*Can cause confusion, since it applies without notice of copyright
*Those wishing to reuse copyrighted works must seek explicit permission
|
*Easy to violate copyright unintentionally, since notification of copyright is not required
|-valign="top"
|GPL
|
*Requires any modified and released versions to have source code available, and to stay under the GPL
*Maintains free software environment
*Based on copyright
|
*Incompatible with closed-source (commercial) development
*Once something is under the GPL, it essentially must stay under GPL
|
*"Locked-in" to GPL
*Forces ideology behind GPL on users of GPL'd content
|-valign="top"
|Lesser GPL (LGPL)
|
*Allows non-GPL software to link with LGPL'd libraries
*Less restrictive than GPL
*Based on copyright
|
*Largely discouraged by GPL proponents
|
*Allows free software to be used in proprietary projects
|-valign="top"
|BSD-style Licenses
|
*Non-copyleft - modified versions aren't required to be free, more flexible
*Allows modified versions to be released under alternate licenses
*Based on copyright
|
*Modified versions can become incorporated into proprietary projects
*Original BSD license had an annoying "advertisement" clause
|
*Free code can be made proprietary
|-valign="top"
|Public Domain
|
*Work is released from copyright
*Work can be used by anyone else without restriction
|
*Any rights by the creator are forfeited
|
*Creator retains no rights to work
|}

==Discussion Questions==

===Adoption of license===
; The Question : ''Should groups like media outlets who desire their content to be shared adopt licenses like creative commons to clarify and guarantee the protections they want to extend to the public?''

Creative Commons licenses are good way for people to clarify what should and should not be done with their work. It lets you pick and choose what rights to reserve. CC licensing must also be indicated, whereas copyright requires no notification. A CC license is a good way to distribute the works you have created and protect the people who download it. If you did not create the work though, you of course cannot give others the right to use it as they see fit. So unless the media outlet is all the creator of all the media they distribute, a CC won't help protect the public.

'''Links'''
* [http://wiki.creativecommons.org/FAQ Creative Commons FAQ]

===Ethical considerations / Obstacles to adoption===
; The Question : ''What ethical advantages and disadvantages are there for adopting Creative Commons licenses? What obstacles exist towards the adoption of Creative Commons licenses within the business community?''

With a Creative Commons license you can allow people to share in your creative work and add to or change things while at the same time reserving which rights you want without giving the public complete free reign over your work. This gives creators more options than normal copyright. This benefit the public but can also benefit the creator by giving them a way to get their work out to the public easier without giving up all their rights to their work.

A Creative Commons license does have some disadvantages though. Once you pick which license to use, you can't take it back. You can choose to stop licensing your work that way but anyone that already has a copy of your work under the old license can forever use it to the full extent that old license permits. Also the most restrictive Creative Commons licenses will still allow restrictive verbatim copying with attribution and non-commercial purposes. This is less than just copyright and may not be restrictive enough for widespread use within the business community. It seems Creative Commons licenses are targeted more towards giving the public greater use and currently don't suite everyone's needs.

'''Links'''
*[http://creativecommons.org/ Creative Commons]
*[http://creativecommons.org/about/licenses/meet-the-licenses Creative Commons Licenses]
*[http://wiki.creativecommons.org/FAQ Creative Commons FAQ]

===Ethical considerations of international usage===
; The Question : ''Copyright law differs between countries. Creative Commons has licenses that can be adapted to be compatible with the laws of many nations. What ethical considerations are there to a system of international copyright laws and/or agreements? Are licenses like Creative Commons viable alternatives to international agreements?''

There are different project groups working to promote the adoption of Creative Commons licenses internationally. They promote but also help adapt the licenses so that they fit with a given country's laws.

An obvious ethical consideration for a international copyright system is that the creator of a work cannot protect their rights if the violator is in another country that does not wish to enforce the licenses. Also legal precedence regarding Creative Commons licenses from one country wouldn't necessarily be recognized by another country. Because the countries of the world don't have a joint judicial system there must a certain amount of trust and understanding between countries in order to protect the rights of all the creative citizens involved. For this reason I think that Creative Commons licenses are a good step in the right direction, but they aren't enough to replace international agreements regarding intellectual property.

'''Links'''
*[http://creativecommons.org/ Creative Commons]
*[http://wiki.creativecommons.org/FAQ Creative Commons FAQ]

2007-07-07T12:26:30Z

Becreswe:

== Spam-Blocking Techniques ==
Domain Blocking 
A spam-blocking technique which consists of redirecting to "junk" email boxes or filtering entirely all emails from specific web domains which have been blacklisted for spamming in the past.
*Advantages:
**Domain-level blocking is an easy and cost-effective way to curtail large numbers of email addresses from which spam is sent. The blocking of a single domain can block an infinite number of possible addresses in that domain.
**Blacklists used for domain-level blocking may be shared among numerous email providers, thus protecting subscribers to one service from spam sent to subscribers of any collaborating service.
**As there is typically a fee associated with acquiring a domain, spammers using blocked domains must pay to purchase a new domain if they are blacklisted.
*Disadvantages
**Though purchasing domains is associated with a cost, it is typically a marginal expense and well within the budget of major spammers worldwide. Thus, blocking a domain does little to prevent a spammer from spamming from a different domain.
**Though spam may originate from one address in a domain, blocking the entire domain may result in the blacklisting of multiple addresses of individuals or corporations which have not engaged in spam, and therefore should not have the receipt of their mail blocked.
**When a web domain previously blacklisted changes ownership, the new owners may remain blacklisted due to the actions of the previous owners, and at no fault of their own.
**Much spam is sent through "spoofed" email addresses in which the sending domain is misrepresented. Blocking such a domain may prevent the receipt of email from a domain which is not associated with spam.
**Spam can be sent from "zombie" machines infected by malware which sends spam, but owned by individuals unaware that their machines are engaging in spamming. Blocking the domains of these machines would block the receipt of mail from innocent users.
**Spam, especially spam from "zombie" machines, can come from typically reputable domains with thousands or millions of users. Blocking such domains may degrade the quality of email service provided to a service's users to an unacceptable level. 
Is it Ethical? 
With so many ways to accidentally block non-spamming email addresses, the ethics of domain-level blocking are questionable at best. The goal of blocking spam is to make email more productive by eliminating messages which would clearly be considered "junk" by the vast majority of users. Taking a serious chance on intercepting email from well-intentioned addresses, therefore, runs counter to the goal of making the communications more productive. Perhaps with a feature to unblock specific addresses from a domain and to receive all messages from a "junk" mailbox, this strategy would be more acceptable. In its most basic form, however, the high probability of blocking non-spamming users challenges this method's claim to validity. 
See Also: 
*[http://www.joewein.de/sw/spam-bl-e.htm List of Blacklisted Domains]
*[http://www.blacklistedip.com/ IP Blacklist Monitoring Service]
*[http://ezinearticles.com/?Blocking-Domain-Spam-Senders&id=374858 Article on Spam which Includes Domain Blocking]

Prior Approval 
A spam-blocking technique in which a sender must request the permission of either a user or an email provider before mail can be received by that user or a client of that provider. This generally takes one of two forms, either the use of a CAPTCHA which a sender must pass in order for an email to be delivered, or a whitelist, controlled by a recipient, which explicitly states the only addresses from which email is received. 
CAPTCHA Approach
*Advantages:
**Completely eliminates the ability of computer controlled spamming "bots" to send mail to an address.
**Allows all mail from human users who can and will evaluate the CAPTCHA, thereby avoiding forcefully blocking well-intentioned human-sent mail.
**Discourages spam sent from human sources to many addresses, as such sending would involved the evaluation of numerous CAPTCHAs
*Disadvantages:
**For the same reason that this method discourages spam sent from humans to many addresses, it also discourages worthwhile messages sent to many addresses.
**Eliminates or severely hampers the user's ability to receive solicited automated emails.
**Does not strictly eliminate spam from human sources.
**Prevents the receipt of mail from the young, the old, the disabled, or others who may be incapable of evaluating the CAPTCHA
**Depending on the implementation of the system, a sender may not expect to be required to complete a CAPTCHA confirmation, and may assume that his or her message has been sent when it has not.
**Rather than eliminating the burden of wasted time and stress imposed by spam, this approach merely shifts it from the receiver to the sender, and imposes it for all emails rather than just spam. 
**Advancing technology makes designing CAPTCHAs which are one step ahead of computer readability increasingly difficult with time. 
Is it Ethical? 
At face value, the CAPTCHA Prior Approval method for controlling spam seems inherently more ethical than the domain blocking approach. However, this approach, too, has the potential to block solicited emails, both from automated services and from those without the ability, knowledge, expectation, or patience to fill out CAPTCHA forms. It could therefore be argued that this approach unfairly targets and limits the ability of various demographic groups, mentioned above, to send email. However, the biggest ethical challenge to the CAPTCHA approach is to ask what, exactly, it does to eliminate the burdens of spam. After all, the act of eliminating spam is hardly an end in and of itself. The point of all spam-controlling technologies is to save time, stress, and annoyance for the users of email. It could be legitimately argued that this approach, while it does cut down on the number of spam messages received by an address, itself creates the same sort of burdens which spam imposes, and thereby does little or nothing to improve the usability of email. The burden of one spam message is merely the time and effort required to read a subject line, identify a message as spam, and click the "delete" button. The CAPTCHA approach eliminates automated spam, and should be lauded for that fact. However, it isn't too far-fetched to say that more time and effort is required to evaluate and answer a CAPTCHA, sometimes multiple times, depending on a user's skill or experience with the tests, than would be required to delete, en-masse, the spam which would be received if this technique were not used at all. In essence, then, this approach merely shifts the burden of wasted time from sender to recipient, and to force such a waste of time on someone who may be busy, who may be sending an important email, is arguably just as unethical as forcing a recipient to delete messages at a time of his or her own choosing.
 
The Whitelist Approach 
*Advantages:
**Allows a user complete and total control over from whom the user wishes to receive email.
**Completely blocks all unwanted mail from addresses which are not pre-approved.
*Disadvantages:
**Fails to block any unsolicited or unwanted messages from pre-approved addresses.
**Blocks all email from addresses not pre-approved, regardless of content, sender, situation, or potential benefit to the recipient.
**Eliminates the user's ability to receive desired or solicited email from unknown addresses.
Is it Ethical? 
Certainly, it would be difficult to defend the ethical nature of forcing users of an email service to employ a whitelist of approved addresses. Whether for business or personal use, the importance of receiving mail from unknown addresses - friends with new or changed email addresses, business associates, new contacts, new clients, individuals who discovered a business via the web - is undeniable in daily life. This approach may eliminate nearly all spam messages, with the exception of spam from individuals the recipient knows, but in the process it impacts the usability of email overall in a very severe, very negative fashion. For many purposes, if an email address cannot receive mail from unknown addresses, it is entirely useless. This approach essentially elevates the errors of the domain blocking approach to an entirely new level of severity. While it may be valuable for applications such as parental controls and monitoring of children on the Internet, this approach is essentially useless for the purpose of blocking spam alone. To force it on a user is to offer a substandard email service, which may be unethical and is certainly undesirable. That said, however, there seems to be nothing wrong with allowing users to choose a whitelist option for controlling email, should they so desire. For a particular email address with specific uses and only a few potential senders, or for an individual who does not wish to be bothered by any unsolicited email whatsoever and who doesn't mind the hassle of learning of new individuals' email addresses by another means, this is an entirely viable option. It is hardly unethical, of course, for a user to choose to seclude themselves from all but a handful of email addresses voluntarily. 
Note that a combination of the above two approaches eliminates many of the problems posed by each. The use of a CAPTCHA authentication system, along with a whitelist of addresses for which the CAPTCHA is bypassed, is a particularly good solution relative to the others discussed here. In such a scenario, unknown email may be received, but spam is effectively blocked or made time-prohibitive. Many of the problems with the CAPTCHA scheme are addressed, as a CAPTCHA only needs to be completed once, after which an address can be added to a user's whitelist, and unrestricted communication may continue. 
See Also:
 
[http://www.captcha.net/ The CAPTCHA Project] 
[http://www.earthlink.net/software/free/spamblocker/faq/ Earthlink SpamBlocker FAQ - CAPTCHA/Whitelist Approach] 
[http://www.netmanners.com/email-whitelist-etiquette.html Article Explaining and Instructing in the Use of Whitelists]
 
Charge for Sent E-Mail 
A method which consists of levying a fee against the sender of an email for each message sent, akin to the electronic equivalent of a postage stamp 
*Advantages:
**Eliminates the positive revenue of sending spam messages, making their sending an undesirable business practice.
**Provides revenue ostensibly for the upkeep and improvement of email networks
*Disadvantages:
**Could make mass emails cost-prohibitive for individuals who need to send out large numbers of messages, or for non-profit organizations.
**Users who already pay between ten and fifty dollars each month for internet service are likely to react poorly to being told that they have to pay more for emails.
**Raises the cost of internet access in general, making it less affordable to lower-income individuals.
**Logistically, imposing a fee on such a global medium as email would prove difficult if not impossible.
**Distribution, use, and escalation of the fee would probably become an issue in time. 
Is it Ethical? 
The ethical nature of imposing a fee for emails is hardly a cut-and-dry question. There does not seem to be anything unethical about charging a reasonable price for a service rendered, and using the revenue from that fee in a responsible manner. However, many would say that it is unethical to charge an exorbitant or excessive fee, or to use the revenue generated by such a fee for irresponsible purposes. Some would argue that current Internet Service Provider charges are already excessive, and that adding a fee for email would only exacerbate an already prevalent problem. One essential question comes down to whether the fee for sent emails is to be used specifically to discourage spam, or whether internet providers might come to rely upon it as another stream of revenue, and as such, seek to maximize the profits they could gain from the fee by consistently raising the price of sending an email. Clearly, the ethics of one use of the fee are an entirely different matter than the ethics of the other. Also, with email being such a pervasive and worldwide phenomenon as it is, the logistics of ethically levying the fee across national boundaries, in various currencies, and in areas where corruption of public office runs rife, becomes a serious issue. It goes without being said that no first-world organization would like to propose a global fee structure which, in another part of the world, might help to finance corrupt leaders, oppressive and inhumane public policies, or terrorism. Thus, the question to whom, ultimately, the revenue of the fee is to be distributed must also be addressed. Also, it would be undesirable for respectable nonprofit organizations to be effectively banned from using mass emails through an inability to afford the necessary postage cost. However, provided that all of these issues could be settled satisfactorily, that there could be exceptions, as with United States postage, for nonprofit organizations, that the revenues were used ethically and fairly, and that the fee was nominal at most, charging a fee for emails sent does seem to be, when properly handled, an ethical proposal. 
See Also: 
[http://www.consumeraffairs.com/news04/2006/02/email_postage.html AOL to Consider Charging for Emails] 
[http://www.infowars.com/articles/ps/internet_tax_email_tax_is_coming.htm Article on a Possible Email Tax] 
[http://www.snopes.com/business/taxes/bill602p.asp An Email Tax Hoax Exposed]
 
Opt-In for Commercial E-Mail 
A technique in which all commercial senders of email would require for a user to take action to choose to have commercial email sent to their address before they would receive any such mailings. 
*Advantages:
**Eliminates all unsolicited commercial emails.
**Allows the user to receive any commercial emails which he or she may choose.
**Does not limit messages sent for personal or nonprofit use.
*Disadvantages
**Disallows any potentially desirable commercial emails of which the user is not aware.
**Requires that companies use other, typically more expensive media to initially contact potential customers.
Is it Ethical? 
Opt-in commercial mailings eliminate all commercial emails not specifically solicited, and, contrary to all above approaches, do nothing to limit or discourage personal or nonprofit use of email in the process. Perhaps it could be argued that requiring all commercial emails to be opt-in would impose somewhat of a burden on companies, but with the availability of other forms of advertising, especially Internet advertising, this would be a marginal burden at worst, and a small price to pay for the near-total elimination of spam. While there are still some minor issues with this solution, such as the possibility that users might occasionally get a spam message that they end up putting to good use, these such concerns are not exactly ethical in nature, and, all in all, the solution of requiring opt-in lists for commercial emails seems like an ethical way to address the problem of spam. However, in practicality, so-called opt in selections are by set to send emails by default, making them, in fact, the much less-desirable form of an opt-out program.
 
See Also 
[http://www.clickz.com/showPage.html?page=3499691 Building an Opt-In Email List] 
[http://www.spamhaus.org/mailinglists.html Comparison of Various Opt-In / Opt-Out Programs as Related to Spam] 
[http://www.spambutcher.com/art1/486278/ Commentary on the Ambiguity of "Opt-In" Programs]
 
Domain Authentication
Domain-authentication technologies are used to ensure that a sender's domain is not forged or "spoofed." 
 
Bounties
 
The "Goodmail" Approach
 
Escrow Bonds
A concept which involves email senders to pay an amount to an escrow service, the sum of which is released back to the sender if a message is not marked by the recipient as spam, but is lost if the message is identified as spam. Variations include adding whitelists for which the escrow is bypassed, and blacklists for which the deposit is automatically lost. 
*Advantages:
**Imposes a fee for emails which is only charged in the case of messages identified as spam.
**Makes spam cost-prohibitive while all other emails, commercial or otherwise, remain free.
*Disadvantages:
**Requires the financing of third-party escrow agencies, allowing a new avenue of exploitation of the fee.
**Necessitates an effective online micro-payment system.
**Allows for the charging as spam of any messages marked as spam, perhaps accidentally, falsely, or maliciously, by the recipient.
**Requires that the logistics of independent escrow agencies for all emails sent in any countries be satisfactorily addressed.
Is it Ethical? 
The concept of an independent escrow system for emails does not inherently seem to pose any sort of ethical dilemma. Such a scenario appears to address many of the concerns with the email postage solution, as, in this scheme, all non-spam emails are free. However, while the concept does not pose any ethical concerns in principle, in practice, several problems arise. Mainly, financing of the escrow services could possibly lead to concerns. Multiple tiers of service, high costs, or "preferred" senders who could bypass escrow blacklists with spam could lead to corruption which would be, in all practicality, unethical. 
See Also 
[http://8stars.org/a/2003/03/13/more-on-fighting-spam/ A Spam Escrow Proposal] 
[http://www.si.umich.edu/about-SI/news-detail.htm?NewsItemID=416 University of Michigan Proposal for A Spam Escrow Service] 
[http://www.itu.int/osg/spu/spam/contributions/Spam%20economics-abm.pdf PDF Presentation on an Economic Bond Solution to Spam]

CSC 379:Week 1, Group 3

2007-07-07T12:24:06Z

Becreswe:

== Spam-Blocking Techniques ==
Domain Blocking 
A spam-blocking technique which consists of redirecting to "junk" email boxes or filtering entirely all emails from specific web domains which have been blacklisted for spamming in the past.
*Advantages:
**Domain-level blocking is an easy and cost-effective way to curtail large numbers of email addresses from which spam is sent. The blocking of a single domain can block an infinite number of possible addresses in that domain.
**Blacklists used for domain-level blocking may be shared among numerous email providers, thus protecting subscribers to one service from spam sent to subscribers of any collaborating service.
**As there is typically a fee associated with acquiring a domain, spammers using blocked domains must pay to purchase a new domain if they are blacklisted.
*Disadvantages
**Though purchasing domains is associated with a cost, it is typically a marginal expense and well within the budget of major spammers worldwide. Thus, blocking a domain does little to prevent a spammer from spamming from a different domain.
**Though spam may originate from one address in a domain, blocking the entire domain may result in the blacklisting of multiple addresses of individuals or corporations which have not engaged in spam, and therefore should not have the receipt of their mail blocked.
**When a web domain previously blacklisted changes ownership, the new owners may remain blacklisted due to the actions of the previous owners, and at no fault of their own.
**Much spam is sent through "spoofed" email addresses in which the sending domain is misrepresented. Blocking such a domain may prevent the receipt of email from a domain which is not associated with spam.
**Spam can be sent from "zombie" machines infected by malware which sends spam, but owned by individuals unaware that their machines are engaging in spamming. Blocking the domains of these machines would block the receipt of mail from innocent users.
**Spam, especially spam from "zombie" machines, can come from typically reputable domains with thousands or millions of users. Blocking such domains may degrade the quality of email service provided to a service's users to an unacceptable level. 
Is it Ethical? 
With so many ways to accidentally block non-spamming email addresses, the ethics of domain-level blocking are questionable at best. The goal of blocking spam is to make email more productive by eliminating messages which would clearly be considered "junk" by the vast majority of users. Taking a serious chance on intercepting email from well-intentioned addresses, therefore, runs counter to the goal of making the communications more productive. Perhaps with a feature to unblock specific addresses from a domain and to receive all messages from a "junk" mailbox, this strategy would be more acceptable. In its most basic form, however, the high probability of blocking non-spamming users challenges this method's claim to validity. 
See Also: 
*[http://www.joewein.de/sw/spam-bl-e.htm List of Blacklisted Domains]
*[http://www.blacklistedip.com/ IP Blacklist Monitoring Service]
*[http://ezinearticles.com/?Blocking-Domain-Spam-Senders&id=374858 Article on Spam which Includes Domain Blocking]

Prior Approval 
A spam-blocking technique in which a sender must request the permission of either a user or an email provider before mail can be received by that user or a client of that provider. This generally takes one of two forms, either the use of a CAPTCHA which a sender must pass in order for an email to be delivered, or a whitelist, controlled by a recipient, which explicitly states the only addresses from which email is received. 
CAPTCHA Approach
*Advantages:
**Completely eliminates the ability of computer controlled spamming "bots" to send mail to an address.
**Allows all mail from human users who can and will evaluate the CAPTCHA, thereby avoiding forcefully blocking well-intentioned human-sent mail.
**Discourages spam sent from human sources to many addresses, as such sending would involved the evaluation of numerous CAPTCHAs
*Disadvantages:
**For the same reason that this method discourages spam sent from humans to many addresses, it also discourages worthwhile messages sent to many addresses.
**Eliminates or severely hampers the user's ability to receive solicited automated emails.
**Does not strictly eliminate spam from human sources.
**Prevents the receipt of mail from the young, the old, the disabled, or others who may be incapable of evaluating the CAPTCHA
**Depending on the implementation of the system, a sender may not expect to be required to complete a CAPTCHA confirmation, and may assume that his or her message has been sent when it has not.
**Rather than eliminating the burden of wasted time and stress imposed by spam, this approach merely shifts it from the receiver to the sender, and imposes it for all emails rather than just spam. 
**Advancing technology makes designing CAPTCHAs which are one step ahead of computer readability increasingly difficult with time. 
Is it Ethical? 
At face value, the CAPTCHA Prior Approval method for controlling spam seems inherently more ethical than the domain blocking approach. However, this approach, too, has the potential to block solicited emails, both from automated services and from those without the ability, knowledge, expectation, or patience to fill out CAPTCHA forms. It could therefore be argued that this approach unfairly targets and limits the ability of various demographic groups, mentioned above, to send email. However, the biggest ethical challenge to the CAPTCHA approach is to ask what, exactly, it does to eliminate the burdens of spam. After all, the act of eliminating spam is hardly an end in and of itself. The point of all spam-controlling technologies is to save time, stress, and annoyance for the users of email. It could be legitimately argued that this approach, while it does cut down on the number of spam messages received by an address, itself creates the same sort of burdens which spam imposes, and thereby does little or nothing to improve the usability of email. The burden of one spam message is merely the time and effort required to read a subject line, identify a message as spam, and click the "delete" button. The CAPTCHA approach eliminates automated spam, and should be lauded for that fact. However, it isn't too far-fetched to say that more time and effort is required to evaluate and answer a CAPTCHA, sometimes multiple times, depending on a user's skill or experience with the tests, than would be required to delete, en-masse, the spam which would be received if this technique were not used at all. In essence, then, this approach merely shifts the burden of wasted time from sender to recipient, and to force such a waste of time on someone who may be busy, who may be sending an important email, is arguably just as unethical as forcing a recipient to delete messages at a time of his or her own choosing.
 
The Whitelist Approach 
*Advantages:
**Allows a user complete and total control over from whom the user wishes to receive email.
**Completely blocks all unwanted mail from addresses which are not pre-approved.
*Disadvantages:
**Fails to block any unsolicited or unwanted messages from pre-approved addresses.
**Blocks all email from addresses not pre-approved, regardless of content, sender, situation, or potential benefit to the recipient.
**Eliminates the user's ability to receive desired or solicited email from unknown addresses.
Is it Ethical? 
Certainly, it would be difficult to defend the ethical nature of forcing users of an email service to employ a whitelist of approved addresses. Whether for business or personal use, the importance of receiving mail from unknown addresses - friends with new or changed email addresses, business associates, new contacts, new clients, individuals who discovered a business via the web - is undeniable in daily life. This approach may eliminate nearly all spam messages, with the exception of spam from individuals the recipient knows, but in the process it impacts the usability of email overall in a very severe, very negative fashion. For many purposes, if an email address cannot receive mail from unknown addresses, it is entirely useless. This approach essentially elevates the errors of the domain blocking approach to an entirely new level of severity. While it may be valuable for applications such as parental controls and monitoring of children on the Internet, this approach is essentially useless for the purpose of blocking spam alone. To force it on a user is to offer a substandard email service, which may be unethical and is certainly undesirable. That said, however, there seems to be nothing wrong with allowing users to choose a whitelist option for controlling email, should they so desire. For a particular email address with specific uses and only a few potential senders, or for an individual who does not wish to be bothered by any unsolicited email whatsoever and who doesn't mind the hassle of learning of new individuals' email addresses by another means, this is an entirely viable option. It is hardly unethical, of course, for a user to choose to seclude themselves from all but a handful of email addresses voluntarily. 
Note that a combination of the above two approaches eliminates many of the problems posed by each. The use of a CAPTCHA authentication system, along with a whitelist of addresses for which the CAPTCHA is bypassed, is a particularly good solution relative to the others discussed here. In such a scenario, unknown email may be received, but spam is effectively blocked or made time-prohibitive. Many of the problems with the CAPTCHA scheme are addressed, as a CAPTCHA only needs to be completed once, after which an address can be added to a user's whitelist, and unrestricted communication may continue. 
See Also:
 
[http://www.captcha.net/ The CAPTCHA Project] 
[http://www.earthlink.net/software/free/spamblocker/faq/ Earthlink SpamBlocker FAQ - CAPTCHA/Whitelist Approach] 
[http://www.netmanners.com/email-whitelist-etiquette.html Article Explaining and Instructing in the Use of Whitelists]
 
Charge for Sent E-Mail 
A method which consists of levying a fee against the sender of an email for each message sent, akin to the electronic equivalent of a postage stamp 
*Advantages:
**Eliminates the positive revenue of sending spam messages, making their sending an undesirable business practice.
**Provides revenue ostensibly for the upkeep and improvement of email networks
*Disadvantages:
**Could make mass emails cost-prohibitive for individuals who need to send out large numbers of messages, or for non-profit organizations.
**Users who already pay between ten and fifty dollars each month for internet service are likely to react poorly to being told that they have to pay more for emails.
**Raises the cost of internet access in general, making it less affordable to lower-income individuals.
**Logistically, imposing a fee on such a global medium as email would prove difficult if not impossible.
**Distribution, use, and escalation of the fee would probably become an issue in time. 
Is it Ethical? 
The ethical nature of imposing a fee for emails is hardly a cut-and-dry question. There does not seem to be anything unethical about charging a reasonable price for a service rendered, and using the revenue from that fee in a responsible manner. However, many would say that it is unethical to charge an exorbitant or excessive fee, or to use the revenue generated by such a fee for irresponsible purposes. Some would argue that current Internet Service Provider charges are already excessive, and that adding a fee for email would only exacerbate an already prevalent problem. One essential question comes down to whether the fee for sent emails is to be used specifically to discourage spam, or whether internet providers might come to rely upon it as another stream of revenue, and as such, seek to maximize the profits they could gain from the fee by consistently raising the price of sending an email. Clearly, the ethics of one use of the fee are an entirely different matter than the ethics of the other. Also, with email being such a pervasive and worldwide phenomenon as it is, the logistics of ethically levying the fee across national boundaries, in various currencies, and in areas where corruption of public office runs rife, becomes a serious issue. It goes without being said that no first-world organization would like to propose a global fee structure which, in another part of the world, might help to finance corrupt leaders, oppressive and inhumane public policies, or terrorism. Thus, the question to whom, ultimately, the revenue of the fee is to be distributed must also be addressed. Also, it would be undesirable for respectable nonprofit organizations to be effectively banned from using mass emails through an inability to afford the necessary postage cost. However, provided that all of these issues could be settled satisfactorily, that there could be exceptions, as with United States postage, for nonprofit organizations, that the revenues were used ethically and fairly, and that the fee was nominal at most, charging a fee for emails sent does seem to be, when properly handled, an ethical proposal. 
See Also: 
[http://www.consumeraffairs.com/news04/2006/02/email_postage.html AOL to Consider Charging for Emails] 
[http://www.infowars.com/articles/ps/internet_tax_email_tax_is_coming.htm Article on a Possible Email Tax] 
[http://www.snopes.com/business/taxes/bill602p.asp An Email Tax Hoax Exposed]
 
Opt-In for Commercial E-Mail 
A technique in which all commercial senders of email would require for a user to take action to choose to have commercial email sent to their address before they would receive any such mailings. 
*Advantages:
**Eliminates all unsolicited commercial emails.
**Allows the user to receive any commercial emails which he or she may choose.
**Does not limit messages sent for personal or nonprofit use.
*Disadvantages
**Disallows any potentially desirable commercial emails of which the user is not aware.
**Requires that companies use other, typically more expensive media to initially contact potential customers.
Is it Ethical? 
Opt-in commercial mailings eliminate all commercial emails not specifically solicited, and, contrary to all above approaches, do nothing to limit or discourage personal or nonprofit use of email in the process. Perhaps it could be argued that requiring all commercial emails to be opt-in would impose somewhat of a burden on companies, but with the availability of other forms of advertising, especially Internet advertising, this would be a marginal burden at worst, and a small price to pay for the near-total elimination of spam. While there are still some minor issues with this solution, such as the possibility that users might occasionally get a spam message that they end up putting to good use, these such concerns are not exactly ethical in nature, and, all in all, the solution of requiring opt-in lists for commercial emails seems like an ethical way to address the problem of spam. However, in practicality, so-called opt in selections are by set to send emails by default, making them, in fact, the much less-desirable form of an opt-out program.
 
See Also 
[http://www.clickz.com/showPage.html?page=3499691 Building an Opt-In Email List] 
[http://www.spamhaus.org/mailinglists.html Comparison of Various Opt-In / Opt-Out Programs as Related to Spam] 
[http://www.spambutcher.com/art1/486278/ Commentary on the Ambiguity of "Opt-In" Programs]
 
Domain Authentication
 
Bounties
 
The "Goodmail" Approach
 
Escrow Bonds
A concept which involves email senders to pay an amount to an escrow service, the sum of which is released back to the sender if a message is not marked by the recipient as spam, but is lost if the message is identified as spam. Variations include adding whitelists for which the escrow is bypassed, and blacklists for which the deposit is automatically lost. 
*Advantages:
**Imposes a fee for emails which is only charged in the case of messages identified as spam.
**Makes spam cost-prohibitive while all other emails, commercial or otherwise, remain free.
*Disadvantages:
**Requires the financing of third-party escrow agencies, allowing a new avenue of exploitation of the fee.
**Necessitates an effective online micro-payment system.
**Allows for the charging as spam of any messages marked as spam, perhaps accidentally, falsely, or maliciously, by the recipient.
**Requires that the logistics of independent escrow agencies for all emails sent in any countries be satisfactorily addressed.
Is it Ethical? 
The concept of an independent escrow system for emails does not inherently seem to pose any sort of ethical dilemma. Such a scenario appears to address many of the concerns with the email postage solution, as, in this scheme, all non-spam emails are free. However, while the concept does not pose any ethical concerns in principle, in practice, several problems arise. Mainly, financing of the escrow services could possibly lead to concerns. Multiple tiers of service, high costs, or "preferred" senders who could bypass escrow blacklists with spam could lead to corruption which would be, in all practicality, unethical. 
See Also 
[http://8stars.org/a/2003/03/13/more-on-fighting-spam/ A Spam Escrow Proposal] 
[http://www.si.umich.edu/about-SI/news-detail.htm?NewsItemID=416 University of Michigan Proposal for A Spam Escrow Service] 
[http://www.itu.int/osg/spu/spam/contributions/Spam%20economics-abm.pdf PDF Presentation on an Economic Bond Solution to Spam]