Firefox has had tabbed browsing for a long time, and it is one of the simplest, yet most loved feature. Tabbed browsing can help increase productivity, because you would no longer hunt for an elusive browser page from the taskbar that contains a few dozen windows.
Tabgroups is a Firefox extension that helps in grouping tabs by adding a think tab bar just above the normal tabs. You can create as many groups as you want and rename them. However, you cannot move the groups themselves, which I consider to be a sore point.

I usually group tabs by the kind of things the tabs are related to – Blogging, Reading and Miscellaneous. Tabgroups was also particularly helpful when I set out to write one of those large list posts, where I typically had 25-40 tabs open at any given time.
Related reading
- Refresh Firefox tabs automatically with Reload Every extension
- Stack Firefox tabs verticaly with Vertigo extension
- Prevent accidental closing of Firefox tabs with Permatabs addon
- BlogRovr Firefox extension: See what other bloggers are saying