Something that you read and it makes your brain hurt because you're actually READING A FUCKING BOOK! Books are popular with nerds who are really smart because they are reading long words and stuff.
Random Guy: Hey man, wanna go read some books?
Some Other Random Guy: NOOOOOOOOOO! I DON'T WANNA READ A BOOK OH GOD THE WORLD IS ENDING!
It's like... Individual tablets, each with words on it to read. It lets you create a video in your mind, like directing your own movie in your brain. It provides data for your brain to keep.