The SkyDrive web service these days is an important part of the Windows 8.1 experience. It has deep integration with the OS and has become a part of the File Explorer and Modern apps.
Sometimes, usually right after installation, Windows 8.1 shows you the "synchronization in progress" overlay icon for one or several of your Skydrive folders.
When you look inside the folder, you will be surprised though that all the contents are already synced!
