How do you get people to come to your site?

[Gutspiller]

I see these forums of 10,000+ members and find out some haven't been out on the Net that long. I was wondering how some of these sites do it. How do you get your registered members so high? I have never liked the idea of restricted access to a forum so tight that they can't even view messages without registering. Just curious on how some of your sites get so big.

Thanks for any info you can provide.