It has become standard practice for professors of mathematics to have a course website with a syllabus and some basic information about the course. The author argues that many professors would be better served by using a course wiki instead. In addition to simplifying all of the tasks of a traditional course website, a course wiki facilitates communication between professor and student and also between students. For the last 4 years the author has been using a course wiki for all of his courses as another means of communication with his students. The article includes a discussion of the motivation for using a course wiki and also describes the technical issues involved in creating a course wiki. (Contains 5 figures and 1 table.)