I would pay for access to course notes that have guarunteed permanence. Because if I ever want to look up an algorithm I learned, and I remember "oh, I remember

I would pay for access to course notes that have guarunteed permanence. Because if I ever want to look up an algorithm I learned, and I remember "oh, I remember that from that one class," I typically look back through my course notes. It'd be awesome to have those notes permanently, without my having to write them up. I know for my school's intro sequence, we post the notes online, but each year the notes change a little, and, if the course is in progress, or just about to start, then only the notes for the course up to the point it's at are available.