I'm not sure I'd say it's sucks, but it does seem to generate more false positives and/or false negatives on forums than it does on blogs. I still think it's useful compliment to Stop Forum Stop or Bot Scout though... I'd rather spend a few minutes clearing the mod cue in the morning then dealing the fallout from the graphic porn spam slipped though during the though during the night.
There can be no 'graphic porn' if you pre-moderate all new member posts, you can do this easy by setting up user groups and move your 'good members' into a Super user group not subject to pre-moderation !!
I tried typepads for 10 minutes and it flagged a number of decent users.....so I am back to manual.
I go through the new signups each morning and look for hints....and also have stop forum spam (only hits about 20% of the time).....but it's easy to tell from some basics.
I also have an IP lookup built into my review screen so I can see if the location matches the required field location they entered.....
It takes me about 5 minutes a day - to go though the 10-20 new signups and do a pretty good job of deleting any suspects.
My users would help me if any got through.