Certainly some are lurkers. I recall a poster on another forum who claimed he lurked for 3 years before posting a single post. Odd, if not creepy, if true....but I doubted his veracity on the subject.
Interesting. I'm still trying to figure this site out. There are some posters who are extremely aggressive and that seems to be tolerated. I've had a few deletions which have led me to scratch my head trying to understand why.