Fame

Fame. It's sort of the whole deal with being a professional personality, isn't it? So, yes, if you become a YouTube personality that anyone's heard of, you'll by definition be famous. Let's be honest here: if you're doing this gig and aren't famous, then you're less of a "YouTube personality" and more of a "really vain person who films himself because he thinks other people care what he thinks."

Sadly, as much as we want to say, "hooray, fame, isn't it wonderful?" the chances that you'll actually succeed to the point of fame in this career are so astronomically low that writing it would actually be a disservice to you. 

Most people in this career are struggling, so rather than preparing for fame, you should consider preparing instead for not-fame. Trying to win fans is great and all, but rejection, negative comments, and low visibility are what you're far more likely to deal with no matter how good your videos are.