Firefox Sync
Firefox Sync is a simple add-on, requiring a user-name, password and phrase(if you forget them you can see them in remembered passwords, assuming you clicked "remember password" when you made it. If you only use one computer, don't bother reading on because it is only useful for people who use firefox on several computers and want the bookmarks/add-ons/history (choose which one/ones) to be the same on all computers! It will automatically not-sync add-ons not compatible with the computer OS for individual computers!https://addons.mozilla.org/en-US/firefox/addon/firefox-sync/