Nigel Gatherer used to have a forum about (mostly) Scottish instrumental music. It gradually stopped working - the forum engine seemed to be unmaintainable. But I see he's just got a new one going:

http://www.nigelgatherer.com/forum/

The old content hasn't migrated (yet, anyway). I've only just joined and haven't got my approval through so I haven't posted anything yet.

It looks a good bit better engineered than the old one.