Well, there is a difference between i) a forum where offtopic threads that are still generally on topic for the board as a whole are allowed, and ii) a forum where any kind of offtopic thread is allowed. This is the former kind; if you look at the other threads in here almost all of them are in some way at least remotely connected to dmoz.org, or resource-zone, or the editing community. (OK, some of them aren't. I have no idea who Dan Rather is or was or why he is gone, but I don't think he's an editor - anyway, that thread is old and dead by now.)
We do remove all threads or single posts in existing threads that are posted solely to promote any particular site, regardless of which forum they are posted in. That includes link exchange requests as well as spammier postings. There is no reason to allow any such posts in the forum - we are absolutely not a venue for advertising.
