Nifty little tool. Rated 5 out of 5 stars

Does what is says and a bit more. It's a placeable element and its look is even a bit customizable. Fonts, font color (sweet if it's hard to read), font size (everything in css format) and even a bit text can be added.
Displayable are the number of all and active tabs and number of tabs before and after the current selected tab.

My only wish would be, that it would auto hide, if a certain number of tabs isn't reached, but you can't have everything.

This review is for a previous version of the add-on (