Although there have been some attempts to teach students “critical thinking skills” with respect to the web, too often these programs adopt a sanctimonious tone, with all the rebellious appeal of extra-credit study hall. The history of antismoking campaigns offers a potentially more effective alternative. Granted, clicking a link or posting a status update won’t give teenagers lung cancer. But the undisciplined use of technology can waste their time, fragment their focus, and interfere with their learning. Just like their health, young people’s attention is a precious resource, and they should be empowered to resist the companies that would squander it.