I think it might be robots judging by the frequency WineHQ is being hit by spammers. phpBB is the number 1 target of all forum motors. I don't remember when registering but did you implement some sort of CAPTCHA? http://en.wikipedia.org/wiki/CAPTCHA This kind of things are new to me but I think this is the first measure you take against all the circulating robots on the net. phpBB.com should have some CAPTCHA plugin for these occasions.
