When Apple ( NSDQ: AAPL ) announced plans to open up the iPhone platform to developers and make its many features available for third-party applications, location-based apps startup Loopt found an opening. With the new iPhone SDK, the social mapping and networking service saw an opportunity to harness the cell-tower triangulation features of the first iPhone and the GPS feature on the new iPhone 3G, all while reaching an audience that is very much in line with Loopt's typical user. In a brief interview on Monday, Loopt's co-founder and CEO Sam Altman talked about new areas of growth for the company, hiccups along the way and yep, you guessed it, impressive iPhone usage from Loopt users. "There are definitely new avenues and that's why we like our position," he said. The confluence of newer platforms in mobile and an opening up of the old have all benefited Loopt's opportunity. "Location is the defining element in mobile… In the past six or nine months, location services have really caught the public… It's gone beyond the early adopter phase" iPhone adoption and usage: Adoption tapered off briefly because of an "invite sort-of-fiasco" where multiple contacts in iPhone users' address books were being invited to use the service somewhat unknowingly. The feature, which gave the company problems almost immediately after the iPhone 3G was released, has been completely shut down for the time being. The company's working on a better solu ...