How mobile is Facebook?

"Sixty-five million people regularly use mobile devices to access Facebook, making it one of the largest mobile services in the world," Forbes reports. It adds that mobile users are "twice as active or 'engaged'" with their Facebook accounts than Web-only users. The social site's definitely making mobile a priority, with its updated iPhone app and new apps for Nokia phones, phones running Google's Android operating system, and Palm's WebOS - all in the last month. Facebook has also "played a central role in the launch of Motorola's new smart phone, the Cliq."