I went to two conferences in the last month, and both tried to implement a tool to “replace” the business card (or increase the social interaction depending on how you want to see it).
Technoark used 2D barcode… while it was not, to my knowledge, really implemented (I think the barcode on the badge was just there for “access control”), it is quite easy to push further and think that the by scanning the barcode with my mobile phone I could access an online mobile profile of the person I am talking with and save it for later use.
Lift09 used Poken, a tiny USB device that includes a NFC. When approaching your token to someone else Poken, it blinks and exchange information about your social networks. Back at home you can plug the Poken to your computer that will open a web page on doyoupoken.com and display all the business cards you have exchanged, and you will then be able to access your contact’s facebook or twitter account (assuming they have entered those information on doyoupoken.com).
Because it requires yet another device to carry on, I do not believe that much in Poken (why not the mobile phone ?)
Both technologies are interesting, but I also exchanged business cards :-) I guess it takes time to change habits…