Mozilla Prism (formerly known by names xulrunner or webrunner) is useful to web application developers who wish to create a site specific browser lacking all the menus, toolbars, and the usual chrome of a web browser. Prism will allow a webapp to more tightly integrate with the native OS and desktop user interface.Mozilla Prism should become mature and useful in the Firefox 3.1 launch around January 2009, but there is a Firefox add-on you can try today (be forewarned: it is intended for developers not users at this point).
Mozilla Prism will compete with Adobe AIR. For a comparison read John Eckman.
