Backchannel backlash is swift and merciless. When Plum.com's Hans Peter played a loud REM track behind his ETech 2006 presentation, the IRC peanut gallery roasted him as he spoke.

Every good conference (or every terribly boring one) has its IRC channel, a chat room where attendees can trade notes or, more often, snark about the speaker. ETech 2006 attendees and non-attendees can access #etech on irc.freenode.net, but the conference is just winding down.