onepointone - 8:52 am on Jul 7, 2010 (gmt 0)

Never done blackhat, but from the little research I've done, it extends well beyond manipulating SE's. If you violate anyones TOS or promote ripoffs...

Things like: Stuffing affiliate cookies, automated spamming of forums, forms, or blogs, making people sign up to email lists in order to get a 'gift' they never get, etc. Some blackhat could be illegal. Its not just confined to a nuisance for search engines.