Hmm -- see the article for details. Doesn't look like good news for Adobe AIR, if Firefox 4 goes as planned.
Beard's philosophy is this: The browser needs to evolve. Beard believes the browser concept hasn't fundamentally changed in 10 years. It's still an isolated piece of software, he says. Mozilla Lab's push is to blur the edges of the browser, to make it both more tightly integrated with the computer it's running on, and also more hooked into Web services. So extended, the browser becomes an even more powerful and pervasive platform for all kinds of applications.
At the moment, these are two separate projects Mozilla is running to push out the edges of the browser: Prism and Weave.