Students are bringing the latest devices to campuses expecting to use them as learning tools, and colleges are trying to deliver. Some of the world's best-known universities tried some experiments with a new model of online learning, in which students watch short video lectures, take automatically graded quizzes, and use online communities to work through concepts they do not understand. It is a mix of self-service learning and crowdsourced teaching. Proponents see the mega-classes as a sign that technology on campuses has reached a tipping point, a moment when the lecture model begins to fade in favor of new teaching methods: The hope is that professors will use technology to deliver basic concepts to students online before class, leaving more time in classrooms for face-to-face discussions and hands-on exercises.