We’re not grading here but we do write for each other.
It’s feedback.
Facebook didn’t start with Likes. It was already in our culture. It’s in our culture. Facebook is a reflection of society. In turn it affects us, so that Liking thing with numbers and points increasing still impacts our reward systems. The association makes sense if one is just exposed to those two things. However, point systems are everywhere.
And we are made of numbers.