Since 1986 we have offered courses on special relativity and general relativity in a variety of formats over computer networks nationwide to a mix of high school students, high school teachers, college students, and college professors. Using ideas from many sources, we have evolved a highly structured format that keep students working every day and talking extensively with one another over the conference system. Obligatory student ‘‘Reading Memos’’ bring a flood of comments and complaints essential to evaluation of student progress and revision of the text. We consider possible reasons why these courses from the United States have not worked with participants in Europe, and speculate about possible consequences of future technological developments.