Kind of a broad question. I wonder why people take notes - Is it for studies or learning? Is it just to remember things? Is it to make your own map of your knowledge? Is it because you just want a place to vent out your feelings into the void?
What do you use to accomplish that? App? Paper? A chat room?
It improves recall and comprehension.
Yeppers.
Usually use paper, but GoodNotes is also a good app for this. Combine Cornell Notes with the method of loci and other advanced memory systems (Google Books link) for best results. Huge game changer.