On Seminars, people actually talk a lot more about motivations than when they write in paper. It would be a good idea if there is an online repository where people can upload notes (handwritten, TeXed, or just slides from speaker) from seminars, so that people can share.
A good way to arrange them maybe is by seminar speaker. So overlaps can also be easily detected.
Of course, nowadays there are already a lot of video lectures online. But apparently that's only in some top institutes, and mostly often incomplete.
So I guess my QUESTION is: Do you think it is technically possible? Especially if any website with similar idea exist?...