Mozilla was out showing off their web-based phone at the Mobile World Congress last month, and IDG News Service posted this video of Jonathan Nightengale, Senior Director for Firefox Engineering, demonstrating the phone in action.
The device runs Mozilla's Boot2Gecko (B2G) operating system, which runs all of the phone's applications on the web, and is demoed on the Samsung Galaxy S2. As Jonathan points out, B2G uses APIs for all of the smart phone functions that typically require a native application, such as: phone dialer, camera, text messaging, and geolocation.
You can run on less expensive hardware, because you've got less technology going on under the covers. You don't have to pay the penalty of a big smart phone operating system if you're running directly on the web. But for users, the other advantage is these webs apps that you're pulling down, you can bring them with you everywhere...The one thing that every smart phone has in common, is a web browser.
-- Jonathan Nightengale