Superimposes a grid over websites that maps out the browser sizes of different kinds of users, based on screen resolution statistics from thecounter.com and marketshare.hitslink.com.

Firefox 3.5 introduces a number of new features, as well as additional and improved support for a wide variety of web standards. This article offers an extensive list, with links to articles covering the major improvements.

Bespin is a Mozilla Labs experiment on how to build an extensible Web code editor using HTML 5 technology.

FireScope is a Firefox add-on that integrates with Firebug, to extend it with reference material for HTML and CSS.

All you have to do is get Firefox 3 during Download Day to help set the record for most software downloads in 24 hours - it’s that easy

Seoquake is a powerful, Mozilla Firefox and Internet Explorer compatible, tool aimed at helping web masters who deal with search engine optimization and internet promotion of web sites.

CoScripter is a system for recording, automating, and sharing processes performed in a web browser such as printing photos online, requesting a vacation hold for postal mail, or checking bank account information.

Firefox 3 will support png animations.

The Polar Rose browser plugin for Firefox (Internet Explorer coming soon) lets you discover who's in any public photo.

YSlow analyzes web pages and tells you why they're slow based on the rules for high performance web sites. YSlow is a Firefox add-on integrated with the popular Firebug web development tool.

If you've used the performancing plugin for firefox to post to your blog and are now annoyed by the Scribe Fire link on all your posts. Deepest Sender is a nice replacement.

You love twitter, but its not always there for you. Now it is. Twitter, twitter, everywhere. Send and receive messages to all your fellow twitterholics, right from your firefox browser.

Introducing Operator, a Microformat Detection Extension for Firefox 2

The Aardvark extension was one of my favorite extensions that broke in Firefox 2.0 and now someone has posted a new version that now works.

A Firefox extension that integrates the highly effective methodology of "Getting Things Done" into the popular email service Gmail.