When I first installed MT 3.2 about six wees ago, I wasn't real impressed with the new anti-spam plugin bundled with it, SpamLookup. The instructions are very sparse and not clear at all and the keyword moderation had no keywords in it, I had to go to a WordPress site to get a list. I had to dig around the web to figure out how it works and how to configure it, this article at Learning Moveable Type helped a bunch. As the days went on it seemed like it wasn't really doing it's job as a few comments were getting through. Not too much trackback spam, though, but wait until the spam bots re-discovered my site now that the secret code was gone.
Little did I know that it was working hard without me even knowing it. There are two kinds of spam flags in SpamLookup, Moderation and Junk. If a comment or trackback is moderated, I get an email. If it's junk, however, I get no notice. Checking my site today I found something like 250 junk comments and nearly 1,200 junked trackbacks. That's over 30 pieces of spam silently junked every day for the past six weeks. In fact, between deeting them at lunch and typing this now, SpamLookup blocked 50 more trackbacks and one comment. Wow.
I had thought I was going to end up going back to the secret code thing (which was highly effective) but now I see no need.
