SpamBayes provides excellent spam filtering capabilities for many mail programs. The CoreServer extends that capability to other programs, web applications for example. It is broken into two pieces, a core which contains the classifier, training database and main web interface, and one or more plugins which adapt the core to various protocols. (See the diagram below.)
The first plugin will score MIME documents submitted via XML-RPC. This should allow a wide range of web applications quickly take advantage of spam filtering. Longer term, perhaps the current POP3 proxy and IMAP filter can be rewritten as plugins to reduce duplication in the SpamBayes code base.
(This page currently lives on the MoinMoin wiki because the SpamBayes wiki is a bi behind the times. Perhaps we can upgrade it or move its content to the Python wiki...)