[aik]

I agree, but it does provide value beyond a simple real-life lecture, most notably the fact that you can go at your own pace and rewind/replay at any point. This is huge. In addition, the lectures are much shorter for the most part, which also makes a significant difference.

Concerning the importance of discussion groups, face-to-face interaction, and networking opportunities -- those things are necessary in certain cases, but not all. The courses currently being offered through these sites are most often the ones that don't necessary benefit hugely from these real-life components.