One of the best add-ons for web developers is . Firebug integrates with Firefox to put a wealth of development tools at your fingertips while you browse. You can edit, debug, and monitor CSS, HTML, and JavaScript live in any web page. Related posts: Web Developer’s Toolbox for Firefox IE

Checking links one by one for the nofollow attribute is tedious. NoDoFollow (by Zachary Fox)shows which links on a page have the nofollow attribute and which are regular follow links. Related posts: Screen Capture Firefox Add-on Firefox Firebug Extension Web Developer’s Toolbox for Firefox

By using the Power Twitter Firefox addon you get URL expansion or shrinking, inline YouTube, Flickr, TwitPic, Google Maps, song.ly, search scoped to a specific user, custom settings, @mentions and more.   Related posts: Manage Multiple Users Over Several Twitter Accounts Join Twibes Twitter Groups Find Relevant Followers On Twitter