It looks as if the previous YouTube Edu Mathematics page has now been split into finer sub-collections.
See http://www.youtube.com/education?category=University/Mathematics
However it may be that the selection process is currently imperfect: if you look at what they have showing for “Pure Mathematics”, there is no-one there yet except for me!
See
http://www.youtube.com/education?category=University/Mathematics/Pure%20Mathematics
Joel
