The Chronicle of Higher Education takes a look at Peer 2 Peer University (P2PU), a three-year-old online institution where students learn together, at no charge, using materials found on the Web. At a time when free online courses are enticing students with the opportunity to learn from star professors at prestigious colleges, P2PU is questioning whether instructors are needed at all. At P2PU, anyone with a passion for a topic can set up a course.