Well many people asks this: social media or not social media? Personally I'm using twitter, tumblr and recently also google+. The problem is that youtubers that are big now started in a period where social media promoting wasn't so necessary but now I think that we should do a bit of self advertising, but be careful to not become a spammer because that will be a double edge sword! A method that can be used is the spread word: you can speak with a couple of friends, who will eventually speak with a couple of friends and so on (maybe you won't obtain the biggest success doing this but it's something!)