Mozilla goes chromeless so you can build your own browser
The browser now know as Firefox began as an effort at Mozilla to create stripped down faster version of the Mozilla Browser suite. It now seems that Mozilla is considering the same thing again -- this time a stripped down version of Firefox called 'chromeless'.
No, chromeless is not a swipe at Google Chrome.
Chrome is the browser window in Mozilla and always has been. The general idea behind chromeless is to strip away the extra shell to make for a faster and more streamlined browsing experience. With chromeless, Mozilla wants to enable developers to be able to build their own browser.
Prism which essentially creates a minimal, chrome-less browser window for a web-application is also an interesting effort, though it seems to have stalled lately in terms of developer releases.