I'm a member of another book forum (don't worry, I won't mention it!), but it's part of a bigger forum provided by my ISP provider - it's like 'general chat', for example, in this forum. It moves very slowly - about two new threads per week.
I was frustrated on Friday night with the lack of decent discussion, so I put 'book forum' into the Yahoo search facility, and voila!
So glad I found it.