DescriptionEdit

SpamAssassin is a mature, widely-deployed open source project that serves as a mail filter to identify Spam. SpamAssassin uses a variety of mechanisms including header and text analysis, Bayesian filtering, DNS blocklists, and collaborative filtering databases. SpamAssassin runs on a server, and filters spam before it reaches your mailbox.

... if this is the spamassassin wiki, what is http://www.exit0.us/ ?

We do need to add that one, perhaps as Exit0.us or Exit0Wiki. On their front page, they refer to this one as The Official SpamAssassin wiki.