Firefox 4 Details
“Beard's basic push is to un-isolate the browser. He says that after 10 years the browser still remains isolated from your browser on other machines and from your computer environment. This leads to the focal point of Mozilla's efforts for Firefox 4. Mozilla is pushing strongly for two very different new lines of research: Prism and Weave.”
Prism's function will be to meld online and offline applications. As Beard described Prism, it should enable users to utilize web applications without being online.