Loopt, a location-based social networking service
, will be the first third-party iPhone service to work in the background while the app is not running.
Via a deal with AT&T, and with your permission, Loopt will be able to access your location all the time you have a network connection, even when you're not actively using the iPhone app. (The app isn't running in the background; it's working server-to-server.) Loopt cofounder and CEO Sam Altman tells us that it's been users' most requested feature.
The basic idea behind Loopt is a map showing where your friends are at the moment, and some other location-based social networking features, like a "who's nearby" list. But because Apple's iPhone doesn't yet support background processing for third-party apps, Loopt ordinarily only knows where you are when you're actively pinging its servers
. That's not as useful. (And a limitation Loopt doesn't have to deal with on other platforms.) But that's changing via this new deal.