That's really up to the users IMO. Off-topic discussion serves mostly forum actives, not the masses.
hmm I would argue that the masses don't use the forum.
Sure, majority of BB users probably don't use the forums (regularly anyway). But most people are usually happy to just read, and most of them don't even want to spend a lot of time doing that. I have seen very different numbers over the years for different types of Internet forums, mailing lists etc. Anyway, the often quoted ratio is 90-9-1 for lurkers, time-to-time contributors, and heavy contributors ("no-lifes"). Some estimates based on studies (where the total population is however usually relatively small and the field of discussion is fairly narrow) go as far as claiming 50/50 between lurkers and contributors, but based on my own experience I believe the typical ratio is closer to 90/10. In BB, most of those who have found the forums have probably posted at least once, because that is required to complete the tutorial.