Noted: Competitors to Facebook that harnessed the powers of social media only in an effort to make us wiser would probably be niche services, like National Public Radio and PBS. “Most people aren’t that fussy,” says Jack Mitchell, a journalism professor at the University of Wisconsin and the author of Listener Supported: The Culture and History of Public Radio. “PBS’s market share is not that high. Public radio is a little higher. It’s a minority taste.”