Blocks annoying video ads on YouTube, Facebook ads, banners and much more.
Adblock Plus blocks all annoying ads, and supports websites by not blocking unobtrusive ads by default (configurable).
Xmarks is the #1 bookmarking and open tab add-on. Keep your bookmarks, and open tabs backed up and synchronized across computers and browsers. Mobile phones with Premium access. Utilize LastPass to sync passwords!
Note from Mozilla: This add-on has been discontinued. Try WebMail Notifier instead.
The original notifier for Gmail.
Popup chinese dictionary for English-speakers learning Mandarin.
An extension that allows for the use of dynamic commands in Firefox.
A maintained version can be installed via: https://bitbucket.org/satyr/ubiquity/downloads/tip.xpi
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