15, Yelpa Web site that reviews shops, restaurants, and night spots and that on Jan.

27 announced a round of funding worth up to 100 millionintroduced the ability for users of its iPhone app to check in at businesses.Now, as tech industry heavyweights such as Google GOOG, Apple AAPL, Microsoft MSFT, Twitter, and IACInteractive IACI try to capitalize on the smart phone explosion with mobile ads that target people where they congregate, startups compiling a trove of data about users migratory habits could make attractive acquisition targets for those companies, adds Ricadela. At one point in January, a Foursquare user was checking into a location every second, the company said.Thats a sign that the people who are into sharing their location are really into it.