Now Loopt says it has found a way around the obstacle. The Palo Alto-based startup Friday announced that it has harnessed networking partners to deliver a solution ahead of location-awareness rivals such as Google Latitude, Brightkite and Whrrl.

These services, most popular among "early adopter" tech consumers, create a kind of sixth sense for the cell phone, alerting users about the proximity of friends, associates and perhaps romantic prospects who also use the service. Alerts can be generated for favorite interests, such as a bookstore or pizza joint.

The ability to operate in the background "has been our most-requested feature since the day we first launched on the iPhone a year ago," said Loopt founder and CEO Sam Altman.

"Other apps will no doubt sprout this same background functionality, but not overnight," observed Paul Boutin of the tech news site VentureBeat. "For now, Loopt is ahead of the pack."

The "Always-On Location Service for the iPhone" required considerable technical work, Altman said, as engineers puzzled out a solution involving "six or seven" partners in the networking infrastructure. "We do it all on the network. Nothing on the phone, so there's no battery impact at all." The iPhone blocks apps from running in the background to conserve battery power.

The company is offering a 14-day free trial, with service starting at $3.99 a month.

While unwilling to divulge specific numbers, Altman said Loopt now has "millions" of users across the country. The company has "40 to 50" employees, he said.

Loopt has been heralded as one of Silicon Valley's most intriguing startups in recent years, in part because of its roots. In spring 2005, Altman was a sophomore computer science major at Stanford when he noticed how often classmates would call friends on cell phones and ask, "Where are you?"

As Loopt's Web site recounts the tale, Altman turned to friends and eventual co-founders Nick Sivo and Alok Deshpande, saying: "Wouldn't it be great if I could open my mobile phone and see a map of where all my friends are?"

The business was nurtured in the Y Combinator startup incubator and later snagged $5 million in funding from Sequoia Capital and New Enterprise Associates. The company has since raised strategic investments from major telephone carriers.

Loopt has also branched into social networking with its Loopt Mix service. Users who express an interest in technology, bicycling or dating, for example, can be aware when others expressing those interests are nearby. Another "social mapping" startup, Skout, is also promoting the Cupid functionality.

And for users not in the mood, Loopt enables them to hide their location.
___

(c) 2009, San Jose Mercury News (San Jose, Calif.).
Visit MercuryNews.com, the World Wide Web site of the Mercury News, at http://www.mercurynews.com
Distributed by McClatchy-Tribune Information Services.