The term non-place was coined by French anthropologist Marc Auge to describe places that are designed to be passed through rather than interacted with. One's personal identity is meaningless in such a space - Auge originally was taking about generic architecture such as modern supermarkets, airports, and malls. They are the same wherever you go; for example, other than the language on the signs, it would be difficult to know where you were in the world if you suddenly woke up in an airport. There is no sense of place, of history, or even of time passing.
Iverson is comparing YouTube to such places. YouTube has no personal interaction component, and its content could be coming from anywhere. Additionally after you've watched enough videos, they all start to seem the same.