Small "on re-reading this" edits almost immediately after publication.
You may have read this fierce critique of one of Udacity's courses by Daniel Collins, an experienced and articulate community college maths teacher who will for sure appreciate at first hand the challenges faced by students who do not take naturally to learning mathematics.
What particularly caught my eye was the unusually open way in which Sebastian Thrun, founder of Udacity and teacher of the Statistics 101 course has responded to the points made by Collins, and the gracious and constructive way in which Collins acknowledges this.
All three posts are well worth reading, along with their developing discussion-threads.
This is the kind of relatively open and self-critical dialogue that needs to be taking place between people who understand the problems and possiblities of the different kinds of mass courses that are currently under development, and who understand their fields from the point of view of how people learn. And if I am judging the underlying quality of a mass course provider, then its openness to criticisms and the extent to which it is committed to incremental improvement in its provision is a key consideration.