I was on Y!A for quite a while. I reached the dizzy heights of Top Contributor, among many many hundreds, but towards the end Yahoo were penalising me for answering many months (6+) resolved questions, quite a few of which I was awarded best answer, supposedly by someone who was offended by the content given, even when I was being honestly helpful: I came to realise Y!A were policing the site themselves and giving out penalties across this side of the Pond more often than the other side. As a result I became quite disillusioned by Y!A supposed fairness and deleted my account with them. I have not looked back ever since.