A pair of Yale students and brothers, Peter Xu and Harry Yu, built a site that let students plan out their schedules while comparing class evaluations and teacher ratings for the past three semesters. Thousands of Yale students used it, apparently finding it a better resource than similar sites run by the university. But this week, as the "shopping period" where students are able to try out classes and finalize their schedules began, Yale not only blocked the Web site from campus networks, labeling it "malicious," but forced the brothers to take it down or face disciplinary action.