Inside the heart of many modern pieces of electronics lies a technology called Bluetooth. It has nothing to do with either the colour blue, nor with teeth: Bluetooth is simply a brand-name for the ability of electronic gizmos to talk to each other wirelessly using a certain standard.

Somewhat confusingly, the “wirelessness” of Bluetooth is a different sort than that used by “wifi,” the increasingly common way we connect our laptops to the Internet. “Different” in the sense that Bluetooth-enabled gizmos and wifi-enabled gizmos can’t talk to each other (although similar at a more basic level in that they both use little tiny radios).

Bluetooth has been “the next great thing” for quite a while; it’s only been in recent years that enough printers, mobile telephones, keyboards, mice and laptops have had Bluetooth capabilities for regular everyday people to start paying attention.

One of the intriguing aspects of Bluetooth is that its range is quite limited — it’s roughly limited to a space equal to your “personal sphere of influence” — a radius of less than 30 feet, give or take walls and ceilings. This not only saves power, but it’s fundamental to the role that Bluetooth is expected to play, shuffling bits of data to close-by things. In other words, you can beam pictures from your Bluetooth phone to your Bluetooth printer if you’re in the same room as it, but not if you’re three floors away or around the corner.

Which is all a very longwinded introduction to Imity, an idea with supporting website and tools, that leverages the “personal sphere of influence” nature of Bluetooth, along with mobile devices to create what they describe as a “pocket radar.”

Bluetooth devices often need to be on the lookout for other Bluetooth devices. Your Bluetooth phone needs to know if it’s around your Bluetooth computer so it can sync its calendar; your Bluetooth laptop needs to know if it’s around your Bluetooth printer so it can print. So one of the features built in to Bluetooth is the ability to look around for other Bluetooth devices.

The Imity idea is at once elegant and simple: create a little application for Bluetooth phones that’s constantly on the lookout for other Bluetooth phones. When they’re encountered, take note of them and upload what’s been encountered to the web. Then let these new devices be named, tagged and filed away, and subsequent encounters matched against this noted-earlier information.

Imity.com has a more complete and visual explanation of how this all works and why it might be useful.

I first saw Imity in action at reboot, and I got a sort of cook’s tour of the idea from Nikolaj Nyholm as we walked around Copenhagen this spring. The Imity application has gone into beta testing this week; if you’ve got a Bluetooth-enabled mobile device that’s on the list of devices that Imity supports right now, you can sign up at Imity.com.