Ad hoc online-cum-physical social networking

Ben Brown, one of the names I finally met at SXSW this year wrote up a good example of spontaneous social networking on his Intarweb Rockstar blog: Virtual Community Boards, Missed Connections Not Missed, and Ambient Noise
Bonus: Jeff Veen blogged his own comment at the “leveraging solipsism” panel about the best way to continue the conversation, which also points to the benefits of ad hoc solutions over yet-another-signup lock-in solutions.
Unrelated: My wiki is down. (Follow the “about me” link in the home page navigation to see the error message.) Are there any phpwiki mavens who want to help me diagnose the problem? I have no idea what caused it or when it started.