I'm taking Modern and Contemporary American Poetry (ModPoPenn) and I'm thoroughly impressed by the fact that the professor, Al Filreis and his staff of TAs maintain a strong presence in the forums. The discussion format videos are excellent and the team is doing a super job of making this voluntary learning experience an extremely valuable one. The coursera.org platform is easy enough for my Mom to use. Now, as far as I can see, the only barriers to entry are background skills and commitment.
Yeah, the ModPo class is impressive thus far. They are producing a ton of content in the video roundtables, and the prof seems to have endless enthusiasm for the online forums. It's a tough subject to teach remotely, but they're really pulling it off.