Integration of SpamAssassin


Now about 20 different integrations that I know of

Integration into MTAs: sendmail "milters", qmail-scanner, Exim, Postfix

Integration into virus-scanner MTA plugins: MIMEDefang, amavisd-new

IMAP/POP proxies and clients

Plug-ins for Windows clients: MS Outlook, Eudora

Also unofficial hacks adding SpamAssassin filtering into mailing list software etc.

Plus the usual mail filters for "normal" UNIX users: procmail, mailfilter, Mail::Audit plugin etc.