Jambo
Jambo is a new startup trying to do location-based social networking. You run Jambo's application, and it tells you about people who are near you (physically) that have the same preferences as you (logically). They have partnered with MacWorld to "Jambo-ize" the conference, so I downloaded the thing before hitting the show. But I forgot to play with it today during my afternoon blogging session, so I can't really speak to how well it works.
I did find the Jambo booth on the floor today, and I grilled one of the co-founders about how this thing works. It appears to ascertain location based upon the MAC address of the wireless base station. In the MacWorld case, the Jambo guys have sniffed all of the MACs for all of the WAPs in the convention center, hotels, and popular SF locations, and entered them into their database. Whenever you associate with a wireless network, the Jambo client sends the MAC address of the WAP to the server, and then they know "approximately" where you are.
So, this makes sense, and fits with their business model. They make money from conferences like MacWorld hiring them to "Jambo-ize" things, to foster social networking in a unique way. They also mentioned bringing their application to Universities, and I think that, if it worked as advertised, Jambo could be a boon in that sort of environment.
Things get a bit stickier, however, in the usage model where Jambo hasn't already cased the joint. If you are sitting on a WAP that Jambo doesn't know about, then it tries to determine your proximity by "hops". Basically, the Jambo client will send not only the MAC address of the WAP that you are connected to, but all of the MAC address from every WAP that your machine can see. Then, they search their database looking for matches.
So, if Bob and Alice are on opposite sides of Sunnyvale, connected to the Internet, they probably won't be able to see any wireless networks in common. But it could be that Bob can see a network that a third user, Joe can also see. And as it turns out, Alice can also see that same network. So now, Jambo knows that Alice is "two hops" away from Bob.
If this all sounds sketchy to you, then you're not alone -- because it sounded damn sketchy to me. I told them that they should do it Web 2.0/Wikipedia style, and have the users enter in location information to the database. There would be some privacy and accuracy issues with this, but it would dramatically simplify the architecture, by harnessing the collective intellect of its users. The co-founder dude didn't seem to be too keen on my idea, however.
Oh well.
-Andy.