Rhodri Marsden: Will Google Latitude invade my privacy?

Cyberclinic

I'm on the train: possibly the four most-used words in the history of mobile communication. Many would be delighted never to have to say, hear or overhear them ever again – and Google is rolling out a service that could make that dream come true. When installed on your phone, Google Latitude lets you see the locations of friends who deign to make their whereabouts known to you, and vice versa.

It's a cute toy: little icons of your chums' faces staring out at you from Cricklewood, or wherever they happen to be at the time – great for arranging spontaneous social events, or ensuring someone gets home safely late at night. But it has provoked fury among privacy campaigners, with one describing Latitude as an "unnecessary danger".

Such services aren't new. Subscription deals offering mashups of online maps and mobile-phone data for concerned parents have been around for five or six years, and services such as Nokia Sportstracker and Brightkite are currently using the geolocation capabilities of iPhones, G1s and other smartphones without getting negative publicity. But when Google moves into the picture, alarm bells tend to ring – not least because of last year's largely misplaced privacy concerns over its street-level photo service, StreetMaps.

Google anticipated the latest furore; Latitude's privacy settings are complex, allowing you to opt in and out, specify how accurately you'd like to be pinpointed for each friend, even manually override it to specify false locations. But that means it's also complex enough for you to make a mistake and leave innocent – or not so innocent – white lies exposed to friends, partners, colleagues or family.

"Keep it turned off – easy!" is the retort to privacy campaigners. Which prompts the reply: well, what if someone else turns it on if you leave your phone unattended, and adds themselves to your list of friends? Maybe early adopters of Latitude should enable that phone lock.

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