YouTube is a very powerful medium for reaching an audience, and starting the process of earning the right to talk to them. So much so that in the games industry, YouTubers have become the tastemakers who can make or break games, much more so than that traditional press channels of reviews and the specialist press.
A successful YouTuber recently wrote up what it takes to become a successful YouTuber, the financial model, the benefits and pitfalls of signing up to a multi-channel network and the ethical challenges that YouTubers face.
The full post is worth reading. http://www.kotaku.co.uk/2014/09/08/really-takes-youtube-star