Stalking Facebook users with strict privacy settings
This is important, so I’ll try to explain the linked article: The API is what applications and developers use. Applications on Facebook run with their users’ privileges: applications can see anything their users can.
To put it simply: Facebook allows anyone capable of writing, say, a simple but alluring questionnaire access to stuff most users probably think of as visible to friends and site admins only.
All Internet users who think of sharing information on Facebook and the Internet in general as being “kind of private”, should familiarize themselves with data mining. Except for when you forget to log off a service or leave your computer unlocked, the real privacy issues are rarely about what someone is able to see while browsing your inbox for a few minutes. It’s all about what profiling information can be collected over time and which patterns are identifiable in heaps of data.