Man...Math textbook/website/vid overload is making me weep for some reason. Most of this stuff hasn't changed in 200 years. Wtf do we need so many books for? Total failure of Math Pedagogy imho.
I think this is a fair topic to bring up. Between commercial textbooks and freely-distributed PDFs, there is a huge amount of expositional material for any given topic in sub-research level mathematics and one does wonder whether there could be a better method of clustering and ranking the material. (Clustering is probably very doable.)
