"You tube" doesn't mean anything in English. It's just a name they made up.
The term "you freak" is really a kind of insult, like "you idiot!" English people would not typically insert "are" in between, because it would also need "a" ("you are a freak"). Likewise, "you surfboard" doesn't mean anything in English, but that doesn't mean you can't use it, of course.
At a stretch, you could argue that YouTube means "the tube about/for you", but it doesn't mean "you are a tube" or "your tube".