Some internet friends are really internet acquaintances who you meet in one game and they are your friend only in the context of said game. This is like some work, school, activity friends who you never care to see outside of work, school, or that activity. Those aren't real friends either.
Some I have played with across multiple games/platforms for years and have kept tabs with, these are basically real friends who live far away. Those who live close, or I happened to travel near in this context I have met in person and gamed with in person though so I guess they crossed over into the real friend category?