Back in the days of Soviet Union, when there was no Photoshop available and space race was at its peak amazing and beautifully crafted propaganda illustrations were being created.
If you are using Facebook social apps for watching videos, reading content and you don't want your friends or everyone to know about your activity, you can turn this off.
With time it can happen you have a bunch of installed apps on your Windows Phone 8 powered phone you never use anymore, I suggest you to remove them to free some of the storage.