I think this is great and having such high quality level instructors is very good. However, I'd caution the typical view nowadays, especially around here, that this signals the end of traditional college and that we should just throw it out.
Why is it that people (even apparently faculty like Thrun) seem to forget that universities deliver more than just undergraduate education? "Delivering higher education" also means research labs and centers for scholars, graduate education, professional education, executive education, etc. While undergraduate education may be ripe for disruption, there is a serious leap needed to go from there to the complete disappearance of thousands of institutions.
Just look at the numbers: dederal research grants and endowments will sustain at least several hundred universities for the long-term, and other universities that are currently teaching-focused will move more of their efforts to research as students take online classes and stop being paid customers.
The institutions that should be worried are technical colleges (depending on major), community colleges and perhaps state college systems. They are the most likely to be disrupted, particularly if Udacity could offer a more comprehensive curriculum. But Stanford? Or even schools like the University of Florida or UC-Santa Barbara? They have plenty of other income sources, and still have a lot of life in them.