This is definitely one of the more interesting articles I've read over at The Atlantic. I've always wondered why YouTubers talk the way they do. I could never quite put my finger on the exact reason why I noticed this nor could I ever really explain it well enough for somebody else to understand. I always just boiled it down to something you have to hear over the course of watching hundreds, maybe thousands, of YouTube videos. Sadly (or not) that's something I've actually done.
So what is this "YouTube voice"? Well, Julie Beck did some research and with the help of Naomi Baron, a professor of linguistics at American University, boiled the "YouTube Voice" down to several distinct characteristics such as stressed consonants and vowels and often unnecessary elongations of words. If you don't have any idea of what that might mean, The Atlantic article has links to very good examples.