[dang]

In Arc, yes.

Unfortunately not, because we don't know how to write anti-abuse systems that keep working once people know what they are.

[dwd]

Unfortunate but very true; it's always interesting to see what other people have in their bag of tricks - but a magician should never tell.

I would guess that you have rules based on patterns of observed behaviour, and that they do 80-90% of the effective blocking.

[part1of2]

I get it, thanks. Instead, Could you write about them, rather than the code? I'm picturing lessons learned, don't try ABC it's a waste of time, and so on..

[webmaven]

I'd actually like to see a series of 'lessons learned', or 'things we tried that didn't work' (including code, if possible/prudent).