The pitch for the online course sounds like a late-night television ad, or maybe a subway poster: “Learn programming in seven weeks starting Feb. 20. We’ll teach you enough about computer science that you can build a Web search engine like Google or Yahoo,” The New York Times reports. But this course, Building a Search Engine, is taught by two prominent computer scientists, Sebastian Thrun, a Stanford research professor and Google fellow, and David Evans, a professor on leave from the University of Virginia. The big names have been a big draw. Since Udacity, the for-profit startup running the course, opened registration on Jan. 23, more than 90,000 students have enrolled in the search-engine course and another taught by Thrun, who led the development of Google’s self-driving car.