Last Saturday's Will Ferrell-hosted Saturday Night Live contained the 100th Digital Short, a celebratory musical number featuring Justin Bieber, Julian Casablancas, Justin Timberlake, Natalie Portman, Michael Bolton, Usher, Jon Hamm and about every imaginable character from the Digital Shorts. There might not be many more of these; Andy Samberg is rumored to be leaving the show after next week's Mick ...