Allowing your Web browser to determine your physical location opens the door to some seriously nifty features. Some iPhone apps (such as Yelp for iPhone) can help you find nearby restaurants, bookstores, or other places within walking distance, for example. But such functionality, available in the newest Firefox and in Safari on the iPhone, also opens the door to some serious privacy concerns: Where you physically sit or stand at any given moment is deeply personal information that you don't want to give to just any site. I tried the new features to see how the browsers handle such privacy concerns.
Firefox 3.5 works in conjunction with the Google Location Service. If you visit a site that can use your location, a pop-up bar at the top of the page asks you to allow or block the request. Allow it, and Firefox sends your IP address and data about nearby wireless access points to Google. Clicking the ‘remember' box tells it not to ask you again for that site. Google then sends Firefox its best guess of your whereabouts, and Firefox sends that data to the requesting site. Google never learns which site wants the info; and though it uses a unique ID tag for your location requests, the tag is randomly assigned and resets every two weeks, so Google has no practical way to associate you with your browser's where-am-I's.
You can completely disable Firefox's location service by typing about:config in the address field and then typing geo.enabled in the filter box. Double-click the setting to change the ‘true' setting to ‘false'.
To clear a given site's remembered permission to use your location (or to see whether you've already allowed it), visit that site, click the site icon next to the URL, and choose More Information. Click the Permissions tab and change the ‘Share Location' options. To clear out all remembered site permissions (which will also reset other things, such as whether to load images for the site), go to Tools, Clear Recent History. Select a time period, and check the box for Site Preferences (be sure to uncheck the other items, unless you want them cleared as well).
Safari's location service prompts you when you visit, via iPhone, a site that can use your location based on GPS, local Wi-Fi networks, or cellular network data. Unlike Firefox, Safari on the iPhone gives you no option to have it remember your decision; the program automatically saves your choice for 24 hours, then resets. To clear a decision before then, go to the Settings app and tap General and then Reset. Tap Reset Location Warnings. To disable location services for Safari and all other apps, go to Settings, General and toggle the Location Services setting.
Both browsers do well to ask you before sharing your location with a site, but neither browser provides what I'd consider essential information: what the site wants to do with your data. Before you share anything, the permission pop-up should tell you whether the data is necessary to map you, find nearby restaurants, or perhaps display location-based ads--but neither browser offers such an explanation. And as the Center for Democracy and Technology notes, users deserve a way to see easily which sites they've okayed, and to revoke that permission if desired.
At this point, few Web sites employ the location features, but to see either browser's option in action, head over to m.flickr.com and choose the Photos taken nearby option.