It seems like we're in a sort of 'autodidacticism boom'. I see this so much in almost everything now--physics, math, MIT courses online, etc. I think this is symptomatic of how people have lost faith in institutions--be it colleges, schools, govt, etc.--and see the DIY route as being better, or maybe schools are doing a poor job teaching or costs are too high, such as tuition. But why the sudden, huge interest in DIY math and physics especially? I dunno.