"The idea is ... not to be locked to (Google) Checkout, not to be locked to a credit card, but to basically support everything out there as a payment system," Rubin said.

Google aims to prevent fragmentation of the Android platform by controlling access to the Android Marketplace, which is where the value lies for developers, Google's Rubin said. To get into the Android Market, applications have to pass "very basic compatibility tests," available to everyone, that ensure compatibility with Android APIs, he said.

Google continues to plan for new releases of Android about twice a year, roughly for summer and the year-end holiday season, Rubin said. Sticking with the food-oriented naming convention under which it is currently offering the Cupcake version, Google will call its next release Donut and follow that with Eclair and Flan. Social networking will be a major focus of one upcoming release, which will add social elements into "every experience on the phone," he said.

Rubin downplayed the success of Apple's iPhone and App Store, which has continued to overshadow Google's platform in device and application sales since the October 2008 launch of the first Android phone, T-Mobile's G1.

"I don't feel the need to catch up," Rubin said in answer to a question about Android's position among developers. And in the long run, Android will win out with diversity, he said. Recently, a device manufacturer he had never heard of walked into Rubin's office with 18 new devices built for Android, Rubin said.