Looks like our "global" domain setting on the cookie got set to nothing. So, bascially, if you went to
www.macosx.com, and the threads are in macosx.com, the cookie is invalid. I have fixed this, but might require some clearing of macosx.com and
www.macosx.com cookies to fix your issue and to possible resolve any new issues from those trying to log out and not having the ability to do that because of the change.