Off the top of my head; Spammers, advertising bots, malware spreaders, ban evasion, and I'm sure there's plenty more. For example, even with the evil score, we have outbreaks of these types of users, where they bombard the forum with various different things.
Oh got it, in my mind I just lumped together all of them as spammers, be it for advertising or phishing links or PMs, everyone that posts something that is unwanted, that's why I was curious if there are other things people do around that is dangerous which is not involving actual posting.
Well, maybe because the barrier is having a real effect on cutting down we don't see them and we underestimate the dangers but seeing how there are lots of people even in this topic who have one or two friends having problems one must think there might be a lot more that don't know anyone on this forum and just leave. And since you mentioned statistics, it would be really interesting to see how many users are created each month via evil IPs and don't log in again.