Clicking the "Test drive now" button launches a copy of this app on Amazon Elastic Compute Cloud (EC2), a web service that provides on-demand compute capacity in the cloud for developers. When you click on the simulated phone using your mouse, we send those inputs over the Internet to the app running on Amazon EC2 - just like your mobile device would send a finger tap to the app. Our servers then send the video and audio output from the app back to your computer. All this happens in real time, allowing you to explore the features of the app as if it were running on your mobile device.

When Amazon's Appstore rolled out last week , we glossed over one detail that merely seemed neat. Today, we're inclined to say that Test Drive may be the most significant part of Amazon's announcement that day. Basically, Test Drive allows US customers to take apps for a spin at Amazon.com, with all the comfort that their tried-and-true desktop web browser brings -- but rather than sit you down with a Flash-based mockup of the app, Amazon is giving you a taste of bona fide cloud computing with an Android virtual machine.In other words, what you're looking at in the screenshot above isn't just a single program, but an entire virtual Android smartphone with working mouse controls, where you can not only try out Paper Toss, but also delete it, browse through the device's photo gallery, listen to a few tunes, or even surf the web from the working Android browser -- as difficult as that may be without keyboard input. Amazon explains:Today, Amazon's Test Drive is basically just Gaikai for mobile phones -- its purpose is simply to sell apps, nothing more. But imagine this for a sec: what if you could access your own smartphone data, instead of the mostly blank slate that Amazon provides here?