Based on my rather limited experience of these boards, I think BAUT is for anyone with an interest in astronomy... as long as they can take the idea that their ideas may be downright wrong (as has been said), but also as long as they can filter out what they need from the conversation.

One thing that can (and does) happen is that the people with a lot of knowledge spin off into a lot of equations which the person asking the original question has no hope of understanding. This happens a lot on wikipedia - it's a truism that physics articles on wikipedia are written by physicists who all seem taken by the rather quaint idea that the world is populated entirely by other physicists. :P

It's not so bad on BAUT, but some conversations do still take a certain amount of parsing, and I think to a layman, especially one whose first language is not English, may run into a few "chinese whisper" issues...

Of course, variants of this issue do appear on all web-forums in the world, everywhere, no matter what the subject matter. Any idiot can throw up a web forum, but it takes patience and effort on the part of all involved to create a really good web community, and I think BAUT has managed this pretty well...