The site seems to be coming under a lot of bot attacks lately, and it seems the majority are cleaned up quite quickly.
However, bots who post in existing topics are largely overlooked. I've reported numerous posts/users for obvious bot/spammer behaviour via the site report function, yet nothing is being done about them, and I'm sure some other users are doing the same.
There are users on this site constantly being caught out by the bots. They're responding to them, thinking they're genuine contributors, and as such it's wasting their time, whether it's simply reading a topic that's been bumped by a bot or even by constructing a reply to said bot/spammer.