I would say that online lectures and current video-conferencing provides about 80-90% equivalent experience while the class size is above 50 or so; once you get

I would say that online lectures and current video-conferencing provides about 80-90% equivalent experience while the class size is above 50 or so; once you get to smaller classes the online lecture becomes about as worthwhile as a lecture on DVD. Beyond general survey courses it is of marginal benefit to anyone who is not an autodidact. Some of the current high-end video-conference setups come close (e.g. the ones that are basically multiple cameras and a screen that is wall-sized) but these are really only suitable for point-to-point remote learning and not situations where the "class" will be distributed in hundreds of locations.