Update: Physics Overflow is live!I am not taking any positions about these matters – and about the Stack Exchange forums, their contents, and their moderators, among related topics – but this blog entry was written with the only purpose: to allow the exchange of information and opinions between users who are interested in the debate about the sufficiency of the existing forums and about the possibilities to create and sustain new ones (and about their desirability and role).
However, I must assure everyone that it is not easy to create and maintain a discussion forum and to guarantee the appropriate amount of quality traffic, especially if the forum is supposed to be focused on a narrower class of topics than the Physics Stack Exchange – and "purely theoretical" physics questions represent a small subset, indeed.
Years ago, we established a USENET group, sci.physics.strings, that was supposed to be dedicated to string theory and other topics in particle and theoretical physics that aren't beloved by the armchair physicists who dominated in a related and larger USENET group, sci.physics.research.
It was moderately hard to go through the bureaucracy and technical arrangements needed to create a new USENET group. We (with Arvind Rajaraman, Urs Schreiber, and perhaps others) won the existential vote. Hundreds of quality contributions and threads (400+ threads?) were posted but it needed lots of work. The traffic tends to be low especially because serious researchers don't have the free time and desire – or they think that they don't have the time and desire – to discuss on the Internet.
I think that at the end, the USENET group was closed for some technical reasons. Some scripts became dysfunctional on an updated Linux or something like that. I forgot what was that exactly. USENET was arguably an outdated technological framework for any discussions from the beginning of sci.physics.strings, anyway. Those are the reasons why I attribute some credit to the "owners" or "managers" of similar forums and assume that this service they're doing for the world gives them some natural rights, too.
The debaters below are encouraged to maintain some professional tone, especially if they're discussing about the people (and their work) who can't defend themselves here.