Most of them are used to minimalize the UI itself, making more screen space available or to modify the UI so it's more pleasing to my eye.
The first and only download manager/accelerator built inside Firefox!
Restyle the web with Stylish, a user styles manager. Stylish lets you easily install themes and skins for Google, Facebook, YouTube, Orkut, and many, many other sites. You can even customize Firefox and other programs themselves.
Xmarks is the #1 bookmarking and open tab add-on. Keep your bookmarks, and open tabs backed up and synchronized across computers and browsers. Mobile phones with Premium access. Utilize LastPass to sync passwords!
StumbleUpon is the easiest way to discover new and interesting photos, videos, web pages and more, recommended by a community of experts. Tell us what you are interested in and we recommend page after page of amazing stuff you’d never expect to see.
A very compact & highly customizable theme that minimizes space consumed by menu & tool bars without hurting the overall usability. Supports Windows, Mac & Linux.
This add-on allows one to customize the theme "Classic Compact". Options include: 10 different toolbar button sets; turning off gradient backgrounds; OS scrollbars; dark system color support; merging menu bar into one menu button; etc.
View and manage downloads from a tidy statusbar - without the download window getting in the way of your web browsing.
Thanks Tekzilla for your awesome review! Click here to see their video: http://youtu.be/BUDqWrJ-Vao
Add a compact menu button to the navigation toolbar, and hide the menu bar.
This extension adds a new "FaviconizeTab" option to the context menu of the tab...
Autosizes the searchbar as you type, cleans the query or reverts to your default search engine after submitting. Supports almost all themes and various search bar related extensions. Useful for saving space on a small screen.
Extends the Location Bar with set of commands to (Shorten URL's,Copy URL,Search site,Go up, pNg, Tag pages easily ,Navigate through sequential URL's,View page cached version,Surf anonymously using online phproxy servers, Twitter)
Fission combines address bar and progress bar (Safari style). This makes the progress bar more visible and allows for a nice visual effect.
Allows you to open any file from the internet into the OS assigned program. This is similar to IE's 'Open' or 'Run' file download functionality. ...
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