Years ago, when they launched Wave extension, Mozilla were still struggling to complete and integrate a timing function in Firefox.
Because Sync is exactly that: an option to synchronize data between multiple computers.
With Firefox 4 Beta you can synchronize your bookmarks, your history, passwords, web forms information, etc.. Using this synchronization, the user may have the same data on any computer or even phone which uses Firefox.
Panorama, so far known as Candy Tab, provides a practical way to organize tabs. Those who have many tabs open, can now group on various criteria such as media sites, news sites etc..