MIT 6.00 Intro Computer Science (OCW)
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This is a very broad question which could mean a lot of things. MIT stands for Massachusetts Institute of Technology which is considered one of the Top Universities in the world and is located in Cambridge, Massachusetts, USA, near Boston. The MITx is their online offering of free courses and edx is the platform used for hosting their current semester of material.
Yes, the answer above was nice. If you are looking for the course, here is the fixed link. They were having some server problems few hours ago. https://www.edx.org/courses/MITx/6.00x/2012_Fall/courseware/Week_1/ If you have an account, just login. If you don't have an account, it will make you create one.
I have no idea.