It's funny how things go around only to return to the place they started. Sort of. America Online was known in its early days for setting up a 'walled garden' with content exclusively available to its members in easily digestible form, thereby protecting them from the uncharted and potentially dangerous wilderness of the web. The web proved to be far richer and dynamic in its content, and so the walls finally crumbled and the garden itself was swallowed up by the wilderness. Facebook -- and the land rush to this frontier -- seems like a return to a walled garden; except, the garden offers memberships to all for no fee, although you need to play by the rules of the garden.
The formal entrance of Stanford University and now the NEJM into Facebook heralds a new era for institutional education and learning where they interact with students and scholars (not necessarily paying ones) using alternative methods. It's an acknowledgement that not only is the traditional classroom of limited effectiveness but also that there is much opportunity in discovering the benefits of social applications for providing a suitable ambience for an ongoing, socially-embedded learning process.