Collusion is an experimental add-on for Firefox and allows you to see all the third parties that are tracking your movements across the Web. It will show, in real time, how that data creates a spider-web of interaction between companies and other trackers.

… allows you to easily test custom fonts, through the @font-face at-rule, without the need for any CSS coding or knowledge of CSS coding. All you need to do is drag and drop.

What? Sprite Cow helps you get the background-position, width and height of sprites within a spritesheet as a nice bit of copyable css. […] Why?
Automated spritesheet generators are pretty cool, but I prefer the control over optimisation and compression you get by making them manually. However, copying all the positions & sizes from graphics apps wasted a ton of my time, so I made this!

Finds unused CSS selectors.

Online. Worry-free. Upgrade your browser today!

Using an outdated browser makes your computer unsafe. Browse Happy is a way for you to find out what are the latest versions of the major browsers around. You can also learn about alternative browsers that may fit you even better than the one you are currently using.

A fork of Mozilla Firefox 4 for the Power Macintosh and Mac OS X Tiger PowerPC

… your window into the invisible web – tags, web bugs, pixels and beacons that are included on web pages in order to get an idea of your online behavior.Ghostery tracks the trackers and gives you a roll-call of the ad networks, behavioral data providers, web publishers, and other companies interested in your activity.

… article covers essential overview, useful tips and links to some really awesome resources that will help you master this wonderful tool.

a bookmarklet for typographically obsessed web designers. It enables rapid checking of fonts and font styles directly in the browser without editing code and refreshing pages. 2.0’s killer feature is instant drag-and-drop font previewing right in the browser (Firefox 3.6+ only), in any document you’re currently viewing.

an application that lets users split web applications out of their browser and run them directly on their desktop

… an open source bookmarklet that makes CSS selector generation and discovery on complicated sites a breeze.

[...] Wichtig ist [...], dass jeder Gebrach von @font-face auch von font-size-adjust begleitet wird. [...]

This extension generates "Lorem Ipsum" dummy text (the text is taken from the Lorem Ipsum site).

... provides Firefox users with S/MIME support for Gmail. S/MIME support is integrated directly into Google's Gmail web interface. Reading and sending of encrypted mail is supported.

PicLens delivers an immersive full-screen experience for viewing photos on the Web.

the social web browser - blog, flickr, rss, del.icio.us etc.

Determining the colour contrast between foreground and background colours is a time consuming task, but is greatly aided by colour contrast analysers. The problem with colour contrast analysers is that they don't automatically go through all of the possib

Professor X Firefox Extension
The Professor X extension for Firefox let's you see inside a page's head without viewing the sourcecode. One installed the Professor X command is available by right-clicking as well as in the Tools menu. When applied to a pag

optimized Firefox builds for G4, G5 and Intel