IF you use the FB Like button in your forums you should read this:
http://www.searchmarketingman.com/20...utton-bug.html
The Like button messes up the URLs and indexed pages in SE's and makes many pages in your forum blank for IE users, so I've removed it for now until Facebook applies a fix to this.
http://bugs.developers.facebook.net/...ug.cgi?id=9777
It's listed as a priority 5 bug by Facebook now, and that's the lowest priority so it may take a while until it's getting fixed, so the Like button may really mess up your forums now!