The latest example, Sebastian Thrun leaving Stanford for Udacity, comes via Glenn Reynolds.
As I recall, Edward Tufte, author of the wonderful book The Visual Display of Quantitative Information, stopped lecturing at Yale decades ago so that he could "spend more time teaching."
Now Tufte tours the country teaching his one-day course, Presenting Data & Information. My father took it about 20 or 30 years ago and loved it.
Just more evidence of what Glenn calls the higher education bubble. I keep asking academic types whether they're concerned about such a bubble. Amazingly, most have never heard the term.