I'm sitting in a chair backed up against the wall in the large room where Jonathan Abrams, founder of Friendster, gave his keynote address to the sxsw conference. He'd left the room about ten minutes earlier, but I was still there, blogging and checking email. He comes back in. The way the seats are arranged, his path leads past my seat. He notices me. A look of almost recognition passes over his face. He quickly scans my name tag. "Oh, um, hi," he says, each syllable more tentative. We've never met. But when he breaks his stride and looks at me, I have an author's egotistical moment that maybe he's read something of mine. Maybe he's heard of me. As his syllables lag, I see that he's realizing it's a mistake: My face rang a bell, but the name tag damped the bell's sounding. "Hi," I say, in the tone of voice of a stranger who wants to follow up with small talk or a question. "Hi," he says. Opting, quite reasonably, to take this interchange of greetings as concluded, he walks away.