Prism is an application that lets users run Web applications in dedicated browser windows.
Prism is based on the site-specific browser (SSB) model, in which a browser is dedicated to a single website: Web apps launch into a simplified window that is free of browser features and buttons that are not relevant to the application.
When a Web application is served within a traditional browser window, there are frequently redundant buttons. Simple browser buttons -- the back button, for example -- can lead to loss of work or other issues with the current application. Furthermore, if a Web app is open in a tabbed window with other sites and any one of the sites crashes the browser, the application crashes along with all the other sites. Because the Prism interface is discrete, other websites can't crash the application.
Mozilla Labs released Prism 0.9 in March 2008.