Almost all mobile phones on the market today come with Bluetooth technology. One of the interesting things about Bluetooth is that every radio has a unique signature: its Bluetooth address. It is a 6 bytes number where the first 3 bytes represent the radio manufacturer (Nokia, Apple, Motorola…etc) and the following 3 bytes a manufacturing sequence number. This unique number has already been used to identify and track people (http://bit.ly/aDtxTc). One other possible use – that I have not seen implemented yet – would be to use it as a base for a social game or a social application.

At any public place you are staying (public transport, stadium, concert, queue…) try to activate your Bluetooth and scan for available devices around you. You’ll be amazed by the number of addresses you will harvest. As each of these addresses belong to individuals, it is possible to imagine that they could be linked to their owners’ social profiles. This can be done with a small software that would be available on each platform (Android, iPhone, Symbian, Windows Mobile…). This software would capture the Bluetooth Mac Address and allow the owner to register it together with his social information. For instance, I could register my mobile Bluetooth address (F4:FC:32:25:4E:25) with my Twitter account http://www.twitter.com/glagardere and my blog http://mylastidea.com/

The same software would have a scanner function which would allow the discovery of profiles around me.

Some web services are already providing this kind of geo-localization functions (Gowalla, foursquare, Google Latitude) but they are all based either on manual check-in operation, GPRS or GPS triangulation. This means that either they are constraining, not very accurate or they need a GPS (only implemented on a very few phones). In any cases they don’t work in moving environment (bus, train). An implementation with Bluetooth such as the one described here would be accessible to most phones on the market, provided that they have an internet connection.