Robert_Charlton - 5:25 am on May 13, 2011 (gmt 0)
Also "no scientific data"... but when I saw the first Panda winners and losers lists, it appeared to me that the losers included a noticeably higher percentage of sites with user-generated content than the winners did. I didn't look to see whether these were specifically forums.
I continue to be surprised that Yahoo Answers does well. This is organized like a forum, though without the intelligent discussion that the word "forum" suggests. Forums have a built in social aspect as well as a content aspect, though, so I suspect they'll do well to the extent that they're active and popular, even if their material isn't of the highest level.