I remember the early days of slashdot fondly, although I didn't actually make an account until a few years later. It was such an interesting mix of serious discussion, in-jokes, and amusing trolls (even the infamous goatsx troll that I fell for more than once.)

I still think that the moderation and meta-moderation was one of the most interesting experiments in a self-governing commenting system, even though it was clear that it was mostly a failure in the long run. My conclusion is that a site needs hands-on human moderation to maintain quality.

Slashdot is also a perfect example of the general life-cycle of cool social site. Humble beginnings -> lots of interesting people -> own little subculture -> lots of interesting content with some impenetrable in-jokes -> existing userbase ages out as they get jobs or have kids -> less interesting content, more in-jokes -> owners sell -> dry husk of a site remains.