FireShot is a Firefox extension that creates screenshots of web pages (entirely or just visible part). Unlike other extensions, this plugin provides a set of editing and annotation tools, which let users quickly modify web captures and insert text annotations and graphical annotations. Such functionality will be especially useful for web designers, testers and content reviewers.
Firefogg video encoding and uploading for Firefox
prototype Firefox extension that integrates messaging into the browser
Run profile manager and load additional profiles in a new Firefox instance. Switch profiles and cookies of a webpage. Create, delete, edit, duplicate and backup a profile. Synchronize two profiles using Dropbox synchronization. It's also possible to synchronize ScrapBook and Zotero folders.
Your browser trusts many certification authorities and sub-authorities quietly, every time you enter an HTTPS website. This add-on for advanced users reveals when certificates are updated, so you can ensure it was a legitimate change.
"XBookmarks" for "XMPP Bookmarks". It is the Firefox implementation of XEP-0048: http://xmpp.org/extensions/xep-0048.html. You simply need a Jabber account and you can use it. Currently it is very basic, though functionnal, as the XEP is.
Identify is a Firefox extension that combines identities across various social network/media sites and provides you with a profile about an individual.
Firediff is a Firebug extension that tracks changes to a pages DOM and CSS.
