You may notice that in the new people app in windows 8, some of your friends updates are missing. The reason for this is your friend is not being very social, and have set one of their settings up so other apps that aggregate social feeds cannot read them.
It is dead easy to fix, but they have to do it. What they need to do is open up facebook, and click the cog icon in the top right, and then choose privacy settings.
Then choose apps on the left, and then click edit to the right of ?Apps others use?
The following screen shows what you send to other apps, including the new people app in Windows 8. Obvious ones that should be ticked are ?If I?m Online?,? My Status Updates?,?My Photos?,?My Videos?. These are the basic ones, but others can be ticked too.