Plazes is an elegant, simple "geolocation" system that enables interesting "location based services" to be created.
A location based service is a "digital something" that reacts to your location. You're walking by a restaurant, you get reviews from others on your cell phone. You're at school, you see a list of your friends studying in the library. You're traveling in a new city, you find free wifi access points.
For systems like this to work, your digital device -- your laptop, cell phone, PDA, tablet, whatever -- needs to "know where it is." This is a more difficult nut to crack than you might think. Newer mobile phones, for example, have some "figuring out where they are" abilities built into them, but this information is rarely opened up to developers to build applications around, no doubt because mobile providers have plans to sell the information to us in future.
Plazes' elegance lies in its solution to this problem. It's built around the notion that every router connecting to the Internet has a unique identifying number called a "MAC address." Unique in the world. So Plazes is built around identifying the MAC addresses of the routers and tying them, in a central web-accessible database, to information about their location.
When you "join Plazes" by registering at the Plazes website, you can download a little piece of software called a "launcher" that does all this "figuring out where you are" work for you, sends the information to the Plazes server, and identifies you to the world as being "there."
What's in it for you? Me?
What I have been struck by in watching Plazes is that no one has been anywhere near me, hence, a bit like being the only one in a town with a telephone and no one to talk to! --Buzz