"By far the largest number of tab extensions add an item or two to Firefox's defaults. Open Link in..., for example, simply adds the ability to choose whether to open new links in background or foreground tabs or windows. Another small addition is Tab History, which allows new tabs to inherit the history of their parent tabs, thus saving you the need to click back on the parent to retrace your steps.
"Group/Sort Tabs is slightly more ambitious. It groups tabs by host names, or order of opening or browsing. It also lets you set a gap between each group of tabs. It can be especially effective if combined with one of the extensions that color-codes tabs (see below).
"By contrast, Informational Tab is less successful. It tries to improve tabs by adding a progress bar for the opening of the page, a well as a thumbnail of the page and a close button on each tab. The progress bar and close button work reasonably well, but the thumbnail is too small to be of use -- even if you adjust the default, tabs are simply too small for viewable thumbnails."
