Meet your friendly Facebook RFID tag.

Here at Facebook’s F8 developer’s conference, each attendee has a small plastic token attached to their badge. Inside the token is an RFID chip. On the back, there’s a ten-character unique ID code. We’ve all been instructed to go to facebook.com/presence and enter our personal code to activate it.

Once your token number is linked to your Facebook account, you can walk around to each of several readers set up around the venue here. There’s an RFID chip inside this little blue piece of plastic, and at each reader, that chip gets scanned and some sort of post goes up on your Facebook profile’s Wall.

There’s a photo booth — scan your chip and it snaps a photo of you and uploads it to your account. There are gaming lounges, and you can become a fan of whatever company or game is sponsoring that lounge by tapping your chip against the reader.

It’s possible there’s some tie-in to a larger presence-sharing announcement coming later on at the conference. Or, it could just be something born from a keg-fueled discussion by some engineers, as the Presence site on Facebook says.

Either way, as soon as it was explained to me what this little blue dongle was doing hanging off of my badge, my first thought was, “It begins…”