I had a similar experience as Anne-Marie. I had been blogging/Twitter friends with a great lady who ran a local radio station. She invited my business partner, Rustin, and I to be interviewed on her radio show, then we discovered our kids go to the same school and are friends. Very small world. I've met several great blog friends at conferences and local "meet-ups" and it has really expanded my circle of IRL (in real life) relationships.
Toni - I'm hoping to go to Blissdom as well!