A while ago I was getting idiot spammers creating accounts to post their stupid links. I then removed the automatic approval to admin approval. It was annoying to say the least. So then I just started banning them. So far so good. I haven't had any new users in a while.
At what point do they realize they're not getting anywhere?
To come to that kind of epiphany, one would need a brain capable of higher thought. I don't anticipate that happening any time in the near or distance future.
So I've retired a few of my security questions because the correct:incorrect ratio was too close and then added a new one. Also, the banning is doing pretty good still. Here's an update on that.
Some of those are great, but you are missing the ultimate question...
Too obvious. Everyone knows it's 42.
Not if they live in Siberia...