Mozilla has launched a usability test plug-in “Test Pilot” for its open-source Firefox browser, in a bid to make testing and user feedback easier and more attractive. "As a Test Pilot, you will not only be able to try out the newest features and user interface ideas before anyone else, but also see and learn how those results may contribute back to the product design." Once installed, you’ll automatically become a Mozilla Labs’ Test Pilot, and receive the notice for upcoming tests. You will’ve the option to quit tests or leave the platform. If the test requires you to install a new feature or product, the platform’ll ask for your permission. At the end of these experiments, you can choose whether or not to submit your test data.
Download: Test Pilot