Communication Ethics book part for Spam Filtering via Blocking Lists. (This is an automatically generated summary to avoid having huge posts on this page. Click through to read this post.)
in Communication Ethics
Almost completely analogous to how advertisement-filtering proxies can download a list of sites to filter out, a mail server on the Internet can download a list of sites to ignore the mail from. Many such lists exist, one of the most famous being the Realtime Blackhole List, created and distributed by the MAPS (Mail Abuse Prevention System).
Such lists have been used for censorship, deliberately and otherwise, many times already. For instance, see MAPS RBL is Now Censorware. Even if you ignore for a moment whether the precise allegations in that article are true, it is true that the power to arbitrarily block communication for large numbers of people is given to these blocking list maintainers. The point is not that it is bad the power was misused, the point is they should not have this power at all. Spams cost the receiver money, but that still does not justify censorship as a solution to that problem. Instead, other techniques should be pursued.
Once again, the benefits of this scheme are marginal, compared to the significant costs. Not only are these blocking lists not working, there are better solutions that are also perfectly ethical. We are not handed a choice between discarding our ethics or living with spam, we simply must use solutions that do not involve third-party communications not consented to by the sender.
Such solutions include, but are not limited to:
- white lists: Lists of known good addresses that you filter into a special "good" mailbox. This would solve the spam problem almost completely for the large number of people who use email to communication with a relatively small number of people or email lists.
- challenge-response: Whenever an email comes from a new sender, a challenge email is sent back requiring the sender to authenticate themselves, either by simply responding or potentially through more complicated means. Unanswered challenges result in the email being discarded.
- requiring payment: A small fee could be charged for sending email, which could be optionally remitted if the receiver likes the email. It could be small enough to not bother anyone, yet make it prohibitive to spam millions of addresses at a time.
- authenticating the sender: We could require people to digitally sign their email, which uniquely ties the email to a secret key which the user can then choose to accept emails from. Sophisticated variants on this scheme could not only eliminate spam but also allow users to decide how much they can trust certain senders.
- things nobody has come up with yet: Who knows when a great solution will come along?
None of these solutions require third-party influence on message reception. The only unethical solution to the spam problem is blocking lists, which also happens to be worse then all the solutions on that list. (Why are we using it then, you ask? Because it's also the easiest to implement.) Ethics need not tie our hands.