More than once, I've gone to an out-of-town conference and have been surprised to find a coworker there. Once--just once, fortunately--I found out a coworker was there because we both wrote stories on the same topic, and they posted within minutes of each other on our site. The technical term for that is "colossal waste of resources." Or just plain bad planning.
There is a service that could have saved my bacon: Jambo. It tells you who in your social or business network is nearby. It does this by checking to see if people you know are attached to the same Wi-Fi access point (or wired router). It doesn't actually know where you or they are--it just knows who's close. If you want to connect with somebody you know is in your area, you can either shout their name real loud or use Jambo's built-in instant-messaging client.
The service is in early testing on Windows Mobile phones, and cofounder Jim Young told me the company is working on supporting Symbian, RIM, and Palm OS. He wants Jambo to be radio-agnostic--it should help you find your buddies (if they are open to being found) no matter what wireless technology they have.
When the service launched in early 2005, the company intended to build out its own social network, which would link its members together with the Jambo proximity technology. Since then, the founders have realized that expecting people to sign up for yet another social network (technical term: YASN) was not a reasonable model for growth. So they've reset their model and are now selling Jambo technology to existing social network sites. Cofounder Jim Young didn't tell me exactly which companies he's in talks with, but I imagine he's looking to get his technology into MySpace, Match.com, LinkedIn, Plaxo, and other big networks, as well as integrated into IM clients.
Also new is the "missed connection" feature: If you sit down at a Starbucks and power up your laptop, the system can now tell you which friends have been there recently, not just who's there at the moment.
There are clear privacy issues with this technology, but like instant messaging, people who don't want to be bothered needn't install it. And users who want to be left alone can turn off the system or crank up filters so only select contacts can see them.
Personally, I'd like to see this tool used in businesses, like CNET itself, so I would know when my compatriots are nearby when I'm in an airport, at a conference, a hotel, and so on.
Other interesting experiments in finding Wi-Fi access point locations are SkyHook, Wigle, and Microsoft's own Location Finder (part of Windows Live Local [blog post]). Social networking projects that track people and their locations include Dodgeball and Plazes.