CNET How To: Use Firefox 4's App Tabs
It's a major time-killer to sift through your three dozen open tabs looking for a needle in a tab-stack. So it's a good thing that Mozilla has given tabs some long-overdue love in Firefox 4 with App Tabs. Perfect for Web apps, App Tabs makes your must-use tabs easy to find and makes it harder to close them. Check out this tutorial to see how to use them.