In one of the cleverest moves I’ve seen in the war on spam, Habeas is using haiku in email headers to mark mail as legitimate in the eyes of spam filters. Because the header lines contain a recognized and ancient form of artistic expression, they’re covered under well-tested copyright law. Any spammer copying one of these headers is violating copyright on a grand scale, and can be easily prosecuted.
Habeas offers a free individual license to use their SWE system, and the company has partnered with a slew of filter authors and mail providers to support the system, including a number of open source efforts like SpamBouncer and SpamAssassin.
