Facebook Graph API-Fetching status messages

I am fetching walls of friends using the graph API in my .NET ap开发者_Python百科plication.. For some friends i get there complete wall..but for the others few posts are missing...

For some friends status messages set by them on their wall are not coming with the JSON data...while messages posted by others on their wall are being retrieved correctly. When i look at their walls from the facebook website, all the posts are visible. But for some reason they are not being retrieved when i use the API.

What could be the cause of it?

Since the Graph API respects user privacy settings, it is possible that the friends who are posting to your friends' wall have changed their application privacy settings so that their posts are not accessible by third-party applications.