Session Manager saves & restores the state of all windows & tabs. In other words, this extension allows you to save the current state of Firefox (history, text data, cookies) and return to that state at any later moment. Besides the manually saved states, Session Manager automatically stores the current state in case [...]

The Copy URL+ extension enables you to copy to the clipboard the current document’s address along with additional information such as the document’s title, the current selection or both.
You might find this behavior useful when you want to send (IM, email) an interesting link to a friend and out of laziness convenience you don’t want [...]

This extension brings the http://tinyurl.com functionality closer to your fingertips. It will convert a long URL into a much smaller, more managable one which is easier to share through email and instant messanger. This feature is useable from the Tools menu or as a Toolbar Element (Firefox).

Greasemonkey lets you to add bits of DHTML (”user scripts”) to any web page to change its behavior thus allowing you to easily control any aspect of a web page’s design or interaction.
For example, if you’re a Flickr fanatic and enjoy commenting you may appreciate the Flickr Rich Edit script which adds limited rich editing [...]

SessionSaver restores your browser -exactly- as you left it, every startup, every time. Not even a crash will phase it. Windows, tabs, even things you were typing — they’re all saved. Use the menu to add + remove sessions; right, shift, or middle-clicking will delete. “Simple mode” for peace of mind, or “Expert mode” for [...]

TrashMail - Free temporary email forwarding!
No more spam mail sent to your real email address!
When you create a new, temporary email address via trashmail.net all emails to the address will be forwarded to your real email address for the number of times and days you specify. When either limit is reached, the Trashmail.net email address [...]