This is mostly just course material (syllabus, homeworks, readings, reference lists, lecture slides), and as far as I can tell not too many courses still have video streams of lecures online yet, but I hope that keeps increasing. For example, the SCPD at Stanford keeps the videos of classes that are available to professionals online for the general public for the first month of the quarter (then you need a password.) However, some classes and many public lectures are online for free.
For some courses admittedly there is limited value in having just the material online, but I think it's important to share "knowledge" and it's even more important to recognize that this is important (as MIT is doing.)
Business schools in particular I think are bad at this, and I fear the attitude extends to (maybe comes from?) the students. I haven't really thought about it much here, but in the one related discussion I've had here (about a conference we were hosting), the suggestion that we should put many of the talks online was met with the following general attitude: "look I got here, I'm paying for it, so I should be the only one who has access to it." This was the (MBA term warning) competitive advantage.
Maybe it's just a background thing; everyone with a computer science background has at the very least, recognized the value of open-sourcing things. However, I thought this "closed-source" attitude was completely the wrong one to have; at least towards knowledge and learning.
The GSB does have a podcast series, which isn't too bad, but....
The spin around the stuff that is online here seems more calculated; it's consciously used as a marketing tool, more than an attempt to share knowledge; which makes sense, but is not as cool; though...maybe that's expected of a business school?:)
The "share knowledge" approach is risky. It can make the school look bad as much as it can make it look good (what if one course just sucks or is badly organized), and the rewards are extremely questionable, but the romantic in me loves the idea of an institute that is open to trying to educate everybody; that is confident enough in it's system that it recognizes that there is great value from being at the school, the contact with the professors, the other students, the experience as a whole and not just from knowing what to read, and that this will continue to bring students to enroll in it. (the MIT brand name probably helps a bit too though :))
But, this is something that is hard to do! huge risks; huge operational challenges; professors annoyed with the added rigidity, lots of overheads, but to persist and complete it, for no real tangible reward, is truly remarkable.