He appeals to a wide audience imo. While I don't really like his videos per se, I appreciate the work he puts into it.
People like to watch people who freak out in horror movies, or in this case games. PewDiePie was the first (or at least one of) the first to do it, and or to do it in good quality. He realized thsi was a key to success and kept putting himself through horror games to get more people. PewDiePie's main attraction is freakouts in horror games, and he does it well if not the best in the market. He attracts both gamers and non gamers, even people who don't play video games can understand the concept of a Horror game, its the same as a horror movie except that you have to do the acting.
He knows his audience, and he knows how to appeal to them basically.
