I'll let the title speak for itself: All I can think of is that he did his marketing, optimization, and advertising right. Take a look at the "Top Comments" on this video and you'll see exactly what I mean: 90% of them seem to imply that people who weren't familiar with him clicked on his videos. However, he has 4 million subscribers! Now I don't do SEO, but there's still nothing more that pisses me off than horrible content with millions of views. What is going on?