Loopt, the location-based friend-finder, has just snuck an amazing little bonus feature into its iPhone app: It works in the background. As Apple detractors are fond of pointing out: The iPhone can't do this. What's happening?
The lack of background apps, or multitasking, on the iPhone has long been excused by Apple as a way of avoiding precious processor and battery resources being used up, resulting in a less satisfactory user-experience. Some users find it frustrating, others never notice...and Apple's even included a work-around in the form of pop-up "push" alerts that let certain apps warn you of something new in real-time, even when they're not running on the phone.
But background-running is absolutely key to a location-based friend-finder service like Loopt or Google Latitude: These services get continual pings from your phone, precisely identifying your location at regular intervals so that other users can work out where you are. They'll work perfectly as designed on the iPhone of course—as long as you have the relevant app running, which is of course impossible to do 24/7. Since Loopt launched on the iPhone a year ago an always-on facility has been the most requested add-on by users, according to Loopt's founder Sam Altman.
So how the heck has it been achieved? After lots of work, apparently—up to "six or seven" partner companies in the network infrastructure. All this engineering tinkering has resulted in an always-on Loopt iPhone app that runs in the background on the network rather than the phone. Presumably this has a knock-on effect on the precision with which one can be located (the background Loopt app isn't accessing the iPhone's GPS to find out where you are, and it's most-likely using cell-tower triangulation methods, much as Assisted-GPS units do to boost their location-sensing powers).
The upshot is that Loopt iPhone users can transmit their approximate location in real-time, pretty much exactly as the service is designed to work, and the iPhone takes no hit to its battery life as it's all running in the cloud. When you flip on the app itself, to try to locate your contacts it'll of course provide a precise location for you...but in the meantime everyone else can find you anyway.
Is there a network-data privacy issue here, beyond that of transmitting one's location in real-time? It's not clear, but Loopt has jumped the line in front of Google Latitude by being the first LBS to work out how to do this on the iPhone. Similar apps will follow, but don't expect an avalanche of other faux-background-running iPhone apps, as the way Loopt works is pretty specific and many other apps won't be able to pull off a similar trick.