Apple's new iOS 4 operating system for iPhone 3G and above pays close attention to your location, in good and maybe not-so-good ways.
First, the good. The iPhone's ability to track your location and share it with installed apps allows for conveniences such as Google Maps-powered directions from your current location to a destination, or a Yelp search for nearby restaurants. But until iOS 4, privacy-minded users who didn't want to share their location data had only one control option in the iPhone settings: all on or all off.
You can still turn off Location Services (as Apple calls them) for all apps in iOS 4's updated controls. Or you can allow or deny access to your location app-by-app; to do so, select Settings, General, Location Services. A small purple arrow will appear next to the On/Off setting of any app that has polled your location in the past 24 hours. (Note that location-aware apps can continue to track your location when running in the background.)
The purple arrow will also appear at the top of the screen (next to the battery indicator) when an app is tracking your location. Both the arrow indicator and the more-granular controls are good moves.
Collecting and Sharing
In response, Apple listed the ways it collects location data, which include gathering the data along with diagnostic information and pinpointing the location of a phone that's searching for a cell connection if the device has location services turned on.
Apple hasn't said how it ensures that such data can't be traced back to individual iPhone users. As was made clear in the snafu involving Google's snarfing up Wi-Fi traffic from its Street View cars (see "Google's Wi-Fi Spying: What Were They Thinking?"), private data can slip through without careful controls.
iAd, Apple's new ad network, can deliver interest-based ads that might note your recent purchase of a movie on iTunes, or location-aware ads touting deals at nearby stores. To opt out of interest-based ads, head to the designated page of Apple's site, using your iPhone or iPod Touch; unless you disable Location Services completely, though, your phone will send your location to Apple, for conversion into a zip code.
Apple says it doesn't normally share zip codes or other data it captures to deliver mobile ads, but advertisers may request your specific location. If so, you will see an allow/don't allow dialog box.
I've argued in the past (see "First Location-Based Cell Phone Ads Get Privacy Thumbs-Up") that properly handled location-based ads aren't necessarily bad, but Apple should be clear about how it safeguards data.
One final word on iOS 4: If you have an iPhone 3G, don't try to install iOS 4 on it. Previously zippy tasks may become dog-slow after upgrading. It's not worth it.