Christine Riccio, the most popular of the bunch: “I was reading a lot of books, and I had no one to discuss them with. I was like, ‘I’ll be lucky if I ever get 500 subscribers over here.'” She now has more than 400,000. Reporter Concepción de León meets Riccio and several of her fellows at VidCon (yes, it’s sort of like ComicCon, but for videomakers).