When trying to find friends of mine that also use this app and have links from a specific site, I'm getting no results from some friends, but it works great on others. If I use the Graph API Explorer, doing something as simple as /friendid/links returns an empty set. However, I can go to their wall and see links and they have the read_stream permissions granted to my app.
Of note, they appear to have a different Privacy Settings experience as well (completely different set of screens).
Anyone ever seen this? How can Facebook be granted permissions, but not really get them?
It's all to do with the privacy settings of the friend you are trying to access data about. Facebook allows you to set different levels of data that will be shared with apps that have been installed by your friends. By default, the privacy setting is ticked for "My Links", but I imagine that a LOT of people, including me, will have turned this off.
来源：https://stackoverflow.com/questions/8222516/trying-to-read-friends-links-in-facebook-using-fql-why-do-some-friends-return-a