Ifile

ifile is the granddaddy of bayesian mail sorters. It's quite stable and puts its all its working data in a simple plaintext file ($HOME/.idata).

ifile is not just a spamfilter... it sorts mail into any set of mailboxes you choose to specify.

It's easy to train ifile...

cat spammbox | ifile.learn.message spam
cat workmbox | ifile.learn.message work
cat familymbox | ifile.learn.message family
...

Easy to use...

:0 fBw
| ifile.inject.header

:0:
* ^X-Ifile-Hint:\ \/.*
${MATCH}

That's my .procmailrc. It puts the box in the category that best matches.

If ifile makes a mistake, just send the message through ifile.learn.message <category>. That's called TOE (train on error). I use mutt macros to do it automagically.