spam comments

Has anyone else been hit with loads of spam comments on their site? Despite throttling of comment submissions AND the blacklist in the past couple of days i've had 25+ comments hit per day with about 100 in the latest attack. Most of the pages are either bestiality or incest related so have now been banned but its a right pain.
Update Another 300+ spam comments got in. I'm sure that a lot of them should have been picked up by mtblacklist though as they either contained words on the list or should have been triggered by spam. Something is seriously wrong.