It's funny that you mention this. I was just explaining to a young coworker how we basically had social networking in the 90's. My friends and I (even nontechnical kids) all maintained Geocities, Angelfire, and Tripod pages. We'd load them up with free scripts for counters, guestbooks, and cheesy popup messages. Then we'd all link around to each others' pages and follow each other with web rings.

Yes. There are a few smaller webrings about, but blog discovery is a problem unsolved.