And yet people pay thousands of dollars — rather, charge thousands of dollars to their expense accounts — to do exactly that. They attend parties where they can meet exactly the same crowd they just saw last month at Web 2.0 Summit, and before that at TechCrunch50, and before that at Brainstorm, and before that at D6. Round and round they ride, on the tech-junket carousel. Why doesn’t the tech-conference crowd give some of their social-networking tools a try and just gab with each other online?