What do we mean when we say it today?
"Neither here nor there" has been used here, there, and everywhere. It's been an episode title for Fringe, a documentary about refugees, and even a Bill Bryson book. But that's neither here nor there.
Today, we use this term to mean anything that's irrelevant or immaterial. Something can be neither here nor there at school, at home, or at work. As long as something is not important to whatever else is going on, we use it.