The popularity of online courses has led to a new market for online cheaters -- companies that will, for a fee, take online classes and exams for students. This may prove to be a growing problem as some surveys of online courses show that nearly a third of all higher-education enrollments in the U.S. are now online—with almost 7 million students taking at least one online class. Critics say that a more “blended” approach with added interaction between the online student and faculty, and with other students taking the course, can be a safeguard against this kind of academic fraud.