Agreed, it's very hard to get into.
Every time I start on a forum I'm very careful not to write anything useless, silly etc., because I think I'll get banned just for missing a comma.
Also, in bigger communities whatever you write is usually flooded very quickly. And you won't have time to read and reply to everything (it's hard enough on this forum). And contributing to a discussion about anything seems insignificant when your reply lands on page 803, 5 minutes before page 806 is reached.