In my opinion, Statistically speking the Threads, Posts, Members Counts (quantity) - are important to the forum to track and indicate, the contribution of the members (in numbers).
On the other hand, the content (quality) of the post, message, is key important as well.
DRUMMERWORLD OFFICIAL DISCUSSION FORUM Statistics:
Threads: 30,169, Posts: 414,723, Members: 27,715
The back of beyond ...