I'm interested in posting (my own) solutions to textbook problems (that I find interesting) online, as I self-study them. I'd guess some problems may be of interest to others, I get to possibly have discussions about them (maybe I mess up), and I get to practice explaining technical concepts through text (I'm interested in pedagogy). For what it's worth, I'm an undergrad (though soon to be grad) student. Ideally I'd want to do something similar to physicspages.com, though I doubt I'd have the same rigour. I'd be working on a textbook myself and using this as a sort of "learning by teaching" approach.
On the other hand, I know many professors use textbook problems as homework, and a publicly displayed website with textbook solutions might be easy to find on a search engine (so students may just copy). Would instructors think this is inappropriate?
In case it matters, I intend to start with Topological Insulators and Topological Superconductors by Bernevig since this is likely to be related to my PhD topic. (Though this could change on a whim)