Windows 8 Sync Apps is a Metro interface, its syncing feature makes it immensely valuable to people with more than one device, and those who know how frustrating it can be to lose personal data and settings from a crash.
Windows 8 can run a local account, but if you use a Microsoft account you'll be able to sync some apps settings and passwords; Internet Explorer 10 history, preferences, and bookmarks; desktop options such as log-in, lock screen, and colors; search preferences; language preferences; and keyboard and mouse settings.
To set it up, go to the Charms bar, then Settings, and More PC Settings at the bottom of the sidebar. That will open the Windows 8 settings screen. On the left nav, go to Users, then Switch to Microsoft account.