We’re pretty happy to announce that the complete spam protection that WordPress users have enjoyed since Akismet started is now available for Movable Type. We commisioned Tim Appnel to write the plugin, which he finished a few months, and we’ve been extensively testing it to make sure it worked satisfactorily.
It still isn’t 100% to where we want it, as interactions with MT’s built-in spam filters and options can negate Akismet’s effectiveness, but we feel it’s now to a point where it can provide a much better protection than MT users are getting currently.
Of course when it rains it pours, and just a day or two ago Stepan Riha independently wrote another MT plugin. You can download the official Akismet for MT, Stepan’s version, and several other implementations on our development page. Enjoy!