That was the point when Hal Abelson convinced MIT that they should support putting as many courses online as possible (having tenure does give you freedom to do good things): that the knowledge is free and if others can get value from it, that would be great!
But it really is just the course material, with some classes also having lectures. It’s not at all the same as attending. A few years ago I needed more thermo than I had remembered from my time as an undergrad. I actually reviewed the same class number I’d taken decades before and it was hard yakka. I am sure I would not have gotten much out of it if I were just reviewing the material cold, without the in person MIT experience in my past.
For some context, OCW was originally created for the ostensible purpose of providing teachers with the raw materials to create their own coursework. At the time audio and video classes weren't commonplace so it really came from a different place than MOOCs would eventually. (One also suspects that the OCW approach probably helped bypass some of the objections that jumping straight to MOOCs would have generated if it were even possible at the time.)
But it really is just the course material, with some classes also having lectures. It’s not at all the same as attending. A few years ago I needed more thermo than I had remembered from my time as an undergrad. I actually reviewed the same class number I’d taken decades before and it was hard yakka. I am sure I would not have gotten much out of it if I were just reviewing the material cold, without the in person MIT experience in my past.