In an effort to reduce spam on the forums, we installed a system that flags posts containing traits commonly associated with spam (I'll refrain from identifying the specific conditions we look for, as I don't want to give a spammer any ideas).

Unfortunately, legitimate posts get flagged from time to time as well. So, every post that is flagged is placed in a queue where it is reviewed by one of the volunteer moderators or administrators. The legitimate posts are approved for display and the spam is deleted.

It's not a perfect system, but it seems to be helping to keep the spam to a minimum and hopefully it isn't proving too much of an inconvenience to members.