IPhone owners have sharply increased their use of location-based phone applications since the opening of Apple's App Store, says one industry executive.

The number of location "look-ups" has increased to an "unbelievable" number, said Ryan Sarver, founder and vice president of business development at Skyhook Wireless. Skyhook calculates the location of an iPhone by gauging its distance from Wi-Fi wireless Internet hot spots, what Sarver calls a "look up."

Speaking at the Search Engine Strategies conference in San Jose, Sarver said he is prevented by Apple from releasing numbers illustrating the increase. But he said "look ups" have risen.

He estimates 140 applications at the App Store make use of location-based information for tasks such as shopping and finding restaurants using the iPhone.

The iPhone also uses GPS technology to calculate its location.

By Mark Boslet, Editor at large.