Generally, very successful people don't spend large amounts of their time commenting on online forums. In this manner, the biggest 'losers' in the real world, with the most time to waste on the internet, become the biggest 'winners' in the online community.
The end result is that the cultural norms of the online community end up being set by people who are the least qualified to create or enforce any kind of healthy norm.
edit: just wanted to say that I recall reading something similar on a blog a long time ago, although I cannot remember the name of the writer.