Package spamassassin: Information

SpamAssassin provides you with a way to reduce if not completely eliminate
Unsolicited Commercial Email (SPAM) from your incoming email. It can be
invoked by a MTA such as exim or postfix, or can be called from a procmail
script, .forward file, etc. It uses a genetic-algorithm evolved scoring
system to identify messages which look spammy, then adds headers to the
message so they can be filtered by the user's mail reading software.