Mobile device OSes have specialized jobs that other platforms don't, such as running network protocol stacks, carefully managing battery life and handling handoffs among cell towers, Rubin said.

"There's different problems to be solved in different categories of consumer products," Rubin said. "But that doesn't mean that ... one wins and one doesn't win. You need different technologies for different solutions."

Speaking at an event in San Francisco where Google and T-Mobile USA showed off the new MyTouch Android-based handset, Rubin said Google would use the Android Marketplace as a "carrot" to prevent fragmentation of the OS. He also said Google Checkout is just the first of what should be a wide range of payment platforms for the Marketplace.

T-Mobile introduced the MyTouch, a touch-screen device from HTC priced at US$199 with a two-year contract, on Wednesday. It's the second Android-based phone from the carrier. Though other mobile operators have expressed interest in selling their own Android products, T-Mobile aims to keep its dominance, according to Cole Brodman, T-Mobile's chief technology officer and senior vice president for technology.

"We want to go deeper with Android, faster than anybody else will, and further than anybody else will. We'll push it to uncomfortable limits that other carriers won't follow," Brodman said. T-Mobile makes a subscriber's personal and contact information portable across Android phone models and will offer applications for use on all of them, he said.