I haven't tested or significantly examined this yet, but adventurous
souls may wish to try out the 'Bad Behavior' spambot detection &
blocking plugin for WordPress and MediaWiki:
http://www.ioerror.us/software/bad-behavior/
http://www.ioerror.us/software/bad-behavior/installing-and-using-bad-behavi…
-- brion vibber (brion @
pobox.com)