I just signed up for the beta version of Imity. I’m still not sure what to make of it, except that it is freaky.

The idea is a form of augmented reality, or embodied virtuality, or whatever you want to call it. It takes the idea behind social networks like Friendster et al and attempts to replicate them in meatspace (in fact, I suspect they are going to try to tie into existing social networks, so that you don’t have to re-enter all your friends yet another time).

Ok, that’s still pretty vague. Let me try again. You need to have a fairly snazzy cellphone for this to work: the phone is your “presence marker.” You sign up on their website, download a little java app to the phone, and whenever the phone gets in range of another bluetooth device, it logs that event. If that bluetooth device happens to belong to someone you know, maybe your phone will beep at you or something. And later, you can go back to the imity website, and see all the bluetooth-contact events that you logged, and you’ll slap your forehead when you realize your best friend was at the same movie as you, even though you never saw each other.

But the freaky thing is, your phone logs all bluetooth contacts. I went to a coffee shop and logged eight contacts while I was there. Several of these were clearly people using Macs (which all have Bluetooth as well), as they were identified by Apple’s default computer names, “John Doe’s Computer” and the like. So now I can take an educated guess at the names of several complete strangers in a coffee shop. And it will count every time you’re around John Doe’s computer, so that perhaps after you’ve been in the same place at the same time enough, you’ll break down and introduce yourself—”Hi, John Doe. You and I have shown up at the same place at the same time on 37 occasions, so I thought I’d introduce myself.” I don’t know. Maybe not. Like I said, it’s freaky.

It gets even freakier when you imagine matching these bluetooth events against a GPS breadcrumb trail. It’s one thing to look at your imity log after the fact and note “at 17:23, I was near John Doe’s computer” and then try to figure out where you were at that time. It’s another when you know “at 17:23, I was at Clementine coffee shop, and was near John Doe’s computer.” Super-freaky. Then you’d push all that data into Google Earth and develop a model of where people hang out.

Or maybe not you. Maybe Starbuck’s installs Imity-like Bluetooth sensors at all their doors, or better yet, a consortium of retailers that all share this data, so they can work out where people go and when. Even if they spend cash, or don’t spend anything, they can track you via your bluetooth device. Of course, you can also track that they’re tracking you.