I am a big believer in using online resources to enhance my teaching. I want to emphasize that word, "enhance." Not "do." My general biology classes are about one-third online, and about two thirds traditional lecture. Given that I recently put up my Brain Awareness Week presentation, you might look at that and think I'm getting ready to digitize all my lectures into Flash presentations, and could go totally online with my class.
And I'm greatful to Kathy Sierra for articulating so clearly why I'm not going that route, here.
Of course, a more immediate reason I never started to push to completely online teaching was that when I went partially online, I surveyed my students. I got very strong agreement with a statement like, "Seeing a professor face to face on a regular basis is important to me." So on some level, people seem to realize that interaction with an actual person in the same room is important.
It's also why we still go to conferences and give actual presentations in addition to just writing refereed journal articles. Storytelling is deeply, deeply ingrained in the human psyche.