It's not actually that unusual for forums, believe it or not. I have a few who registered for mine who never posted, and I suspect the reasons vary a lot between intending to post but never quite getting to it and registering just to see if there is stuff which only shows up when you register - which is true of some forums (And not just the search functions mentioned by Raze, either <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />).
