New York founder brett martin is presenting at TechCrunch Disrupt his mobile app Sonar.me, which displays people in the room you would want to meet or have friends in common with based on your online social graph. He built it because he used to sit in bars, wanting to meet new friends and Ruby developers, but instead checked messages on his phone from people miles away. “How do I tell people that I want to party tonight?” he asked. “Which I do!” (We hear the unofficial afterparty is with Qwiki and Stylecaster at Casa La Femme in the West Village.)