Internetworkers: http://www.ibiblio.org/internetworkers/

["Michael D. Thomas" <mdthomas AT mindspring.com>]

http://www.silicon.com/a54060

<snip/>
"With a click of the 'block' button, users can forward an offending email to
Cloudmark's databases where "truth evaluation" technology judges how
trustworthy the user is. Criteria such as length of time the user has been on
the network and how accurate their past judgements have been are used to
decide whether a filter will be established. If the email is adjudged to be
spam it is then blocked from all members' inboxes."
<snip/>