Is there a Bayesian filter library for .NET?
I would like to setup a group of folders and have emails automatically moved to those folders based on what has been previou
This totally doesn't answer your question but the product called Popfile does this using a Perl library.
I found Weka.Net which is a port of the Weka Java Machine Learning Framework to .NET. It is an alpha release, and seems not so active, but if it has the core of Weka, you can use it to write what you ask for. Mailprobe "does support N categories, not just Spam/NonSpam" - so maybe this is what you are looking for. This naive bayesian classifier may be helpful too.