(CNN) -- Facebook is, by its nature, a social experience.
But as the undisputed king of social networking expands ways for its users to interact, it's raising more questions about how much of their information is made available to people they don't know.
In some cases, users may not even realize it's happening.
One example is the hundreds of thousands of developers approved by Facebook to create games, quizzes and other applications. Some of those developers are able to access basic information about users after a Facebook friend has started using their application.
Facebook provides pages of instructions on how people can tighten up their privacy settings to hide their personal information from other users and outside applications.
But some observers say that too many of the site's estimated 400 million users don't know how to do so...
