Official eBay add-on. Keep an eye on your eBay activity wherever you are on the web when you install the eBay Sidebar for Firefox. It’s a free tool built with eBay users in mind that will help you get more out of your buying and selling on eBay.
Shareaholic is the easiest way to share interesting links using Facebook, Twitter, Google Mail, Reader, Bookmarks, Evernote, Bitly, StumbleUpon, and more... from one simple ALL-IN-ONE add-on. This is the ultimate tool for the link sharing addict!
Automatically get the lowest price on whatever you’re buying
Comparison shop for the best fares on airline websites. Yapta will track fares for the flights you like and notify you when prices drop.