I know I indirectly referred to the Horses to Water: Why Course Newsgroups Fail study yesterday but it deserves it's own direct link:

It is now fashionable for university administrators to embrace computer-mediated communication as part of their strategic plans, in large part because the medium seems to hold great potential for increasing enrollments and decreasing costs. It also may hold some potential for education. Yet little is known about how much of the educational potential of computer-mediated communication can be realized.