It is, but some things need teachers, or at least slides and tutorials, instead of encyclopedia articles. If I had to learn linear algebra from http://en.wikipedia.org/wiki/Linear_algebra, I wouldn't have gotten nearly as far as I did with Math 54 in college.
Wikipedia can only help if you know what you want to study and know how to move around finding information. For a lot of people in the third world this is not the case. They need mentors and guidance more than the material and information.
Sure, using and creating/improving open teaching material (wiki{pedia/versity}...)should be one major disrupting point in such a university.
But even online you can't neglet two kinds of human interactions: with teachers (much greater level in a field, can play as role models, etc...) and with students. I'm pretty sure they are important while learning! Like irc/online communities, it can be less intense if you don't end up meeting, but i think it's an integral part of learning.
Wikipedia in an encyclopedia, not a tutorial. Its articles are long and well written, but neither complete nor geared towards teaching. Myself, no matter what subject I always go first to wikipedia, but if I want to actually learn something I always google it afterwards.
