I can't believe I missed this. Even worse, it looks like just about everyone did (OK, not everyone). I just checked a GPS-enabled webpage page, below, on a 3.0B5 iPhone's Mobile Safari and Boom! The webpage checks the GPS coordinates of the iPhone and returns a result.
The test webpage was built by Doug Turner for Mozilla's upcoming implementation of the Geolocation API (if you have Firefox 3.5B you can try it out).
Google also mentioned in their Latitude for iPhone presentation last week that they were no longer going to build a native app for the iPhone. They said Latitude was now going to be a WebApp that would run in Safari. That should have tipped me off that Safari would have to be able to not only retrieve others' locations, but also broadcast the location of the user's iPhone.
GPS in the browser is a relatively new trick. The Geolocation API Specification is part of the W3 Consortium's standards but hasn't been finalized just yet. That means that there could be some significant changes to it before it is ratified. Unlikely, however.
Most of the major browsers are planning to include the Geolocation capabilities in future versions of their products. Webkit, which is the basis for Safari, Mobile Safari and a lot of other browsers including Google's Chrome, is also testing this functionality. That is what we are seeing in the new iPhone 3 OS.
How many times have you had to put in your Zip code in your browser to tell it where you are? Looking for restaurants? Bank branches? Auto repair shops? This can now be built into the browser. Adsense and other advertising could even use Geolocation to better serve ads. Surely Facebook and Twitter will use this to
track users allow users to tell their friends where they are.
I can see this blowing up quick. In a few years we'll try to remember what it was like before our browsers knew where they were.