I always thought crowd-sourced feedback on whether a class + instructor combination required the textbook would be incredibly useful.
A) There are 20+ students in typical undergraduate classes
B) Professors tend to teach undergraduate classes extremely similarly from year-to-year
So I imagine it wouldn't take long until I could plug in a school, class, and professor and get a list of impressions back. E.g. "Homework taken directly from book"
Second idea. OCR + diff would be incredibly valuable for version diffs of popular textbooks. How much was rewritten? Were the homework questions changed? If so, which ones?
Thanks for the good work though!