I found this today and I already love it.
It does 2 amazing things:
- Moves the tabs to the left. On a widescreen computer this makes more sense than stealing Y-axis resolution. Also, I have to create a LOT of tabs before I start scrolling, which used to be a frequent annoyance. (If you prefer things to be on top/bottom/right, you can choose that in the preferences.)
- Shows which page the tab 'came from' in a nice tree view. This is so nice for dealing with a tab overload efficiently -- I often find that I am researching several aspects of something at the same time. Even the fact that my tabs can be gathered up under their respective google searches is useful.
You can install it at Mozilla Addons. Check there for more screenshots and a full list of the features.
Here is a simple example of it in action:
