edX is going to be a major flop, like OCW. You heard it here first.
I have no idea what the goal of the project is, but across a wide range of possible goals it will fail miserably.
Why? MIT isn't particularly good at educating it's own "residential" students!
Update: This has been my most popular post so I should add some less factitious comments. The general sense I get from edX, Coursesa, and other massively online courses is that they do not have much in the way of a mission. I can't tell if edX is a motivational product, a learning tool, or what. You could compare it to a gym. Gyms provide free weights, stationary bikes, treadmills, and the like to help you work out. But for most people these machines provide little advantage over just jogging around the neighborhood. edX provides courses, but if they are anything like most MIT courses, they probably aren't much better than a good textbook or notes. Maybe the value of the courses is that they are a motivational device, or a signaling device, but no one has explained to me what they do for people beyond "educating" them and I'm skeptical about that.
I think universities mostly generate value for students by helping them to network with peers and alumni, motivating them to work through nudges like social pressure to attend class and traditional incentives like grades, and signaling that people are "smart" (this interacts with networking). I don't see how edX could be good at any of that anytime in the near future.
That said I don't think edX is a waste of money. With the future of high education so uncertain there is a lot of option value to having an online education system "ready to go" and, as I noted earlier, MIT's undergraduate education is by and large pretty terrible. If MITx courses draw interest from people who care about teaching then perhaps MIT will see a shift of student out of classrooms where the teachers suck and into classrooms where the teachers are passionate about designing good class.