This article in the Times is brilliant...Merce Cunningham classes offered online. Dance and technology merge once again. How cool! I can't wait to see the videos they do, even though I'm not really familiar with his work. It would be great if more master teachers did something like this so that people outside of New York (and those of us here as well!) could learn from them without the hassle of a big master class.
The separation from technology does eliminate that immediate feedback factor of class, but nowadays you're lucky (or, me anyway) if you get attention at all in a class like that.
Anyways, go read about it.