A really tightly written OP (like the ones you always present on Mysteries) can't last sixty responsive and interactive posts before becoming totally unwieldy. Twenty is probably better.
That's my experience with online learning in an academic setting.
Of the 108 or so posts on this thread, I'd guess that more than 80 are empty of content.
When the meaningful content is so scattered, continuity and progress in discussions is almost impossible.
It's a problem on all of the boards. GHMB is very close to becoming a "Trollhouse":