(Found via here). Reuters has an article entitled Schools, tech comPanies tailor social sites for students. The article says:-
Colleges and universities across the United States are going beyond simply creating websites and pages on Facebook for students to "friend" or "fan." They are working with technology companies to build their own social networks and integrate them into campus life to boost admissions and retain students.
Obviously, somethig that could be transfered to a library environment. So, perhaps you could use it for patrons to sponsor books (to increase money's for the library).