Google Offers Tool to Let You Track Your Friends' Movements

Not content with indexing the world's information, Google is now tracking where users of its maps service are, and making that location data searchable by others.

The tracking feature, called Latitude, will appear on compatible mobile devices in a new version of Google Maps, version 3.0.0. It can also be added as a gadget on iGoogle, the company's personalizable home page service.

Tracking people's movements is sure to raise concerns about privacy, but "everything about Latitude is opt-in," according to Vic Gundotra, vice-president of engineering with Google's mobile team, writing on the company's official blog.

The service will indicate users' locations with a small photo icon superimposed on a map. It is initially available for the BlackBerry and devices running Nokia's S60 or Microsoft's Windows Mobile software. An Android version will follow in a few days, said Gundotra, and he expects an iPhone version will follow "very soon."

To begin sharing your location, you must either sign up for the Latitude service or accept an invitation to view the location of someone already using it.

Latitude's help pages describe the fine-grained control the service allows over who sees what, and when. For each friend with whom you choose to share information, you can give your precise location, the name of the city only, or no information at all.

Latitude can automatically detect your location if you're using it on a compatible smartphone -- but it's also possible to lie about where you are, by manually setting your location on a map.