I think Addieu (http://addieu.com http://addieu.com) is doing something like your first point: tap your respective phones to exchange contact info and social ne

I think Addieu (http://addieu.com http://addieu.com) is doing something like your first point: tap your respective phones to exchange contact info and social networks (full disclosure: I'm one of the cofounders, and we're iPhone only right now). As for your second, if you know what your friends look like, you don't need to know exactly where they're sitting, so you don't need RFID. SitBy.Us (http://sitby.us http://sitby.us) illustrates this perfectly: if they found a biz dev guy and expanded beyond SXSW & Mozilla Summit Conf, they'd be killing it. If Lanyrd is smart, they'll snap up or clone SitBy.Us.