Firefox Sync is a service that allows you to synchronize your Bookmarks, preferences, history, add-ons, etc. between all your devices with Firefox. For example, you might have a desktop, laptop, and Android Phone, all with Firefox. By using Firefox Sync, you can make sure that all your bookmarks are on all your devices, so you can always access them no matter what device you are using. How do I set up Sync on my computer?