Forums are not really build on Contests, however the quality of Articles and Posts. It's member interaction has a lot to do with it, thus new members wanting to come, and do the same, mingle with the rest.

I could possibly tell you, if the Marketplace would be suspended for a couple of weeks, people would slowly decline. Their are a few old skoool ( ) members that post a heck of alot more, quality posts and quantity wise, than new ones; this includes me.