Trendhunter recently wrote that actors were starting to get hip to the idea of viral videos as a way to boost their image (in response to the Matt Damon/Sarah Silverman instant classic), and I could not agree more. Once I see a celebrity in a viral video parodying themselves, I think they have a fantastic sense of humor and don't take themselves too seriously — that latter quality being something that is normally antithetical to the image of actors, who are generally perceived as egotistical bigheads with a deep need to be taken seriously. Will Ferrell's FunnyOrDie (their original post being the amazing "The Landlord") has helped in this phenomena, and before sites and actors cropped up trying to create virals, YouTube really boosted the idea — would you have seen Justin Timberlake's "D*** in a Box" video if it had only aired on SNL? Probably not.
Will these videos enable stars to make their movies and TV shows hits? Maybe. They make me snort coffee onto my keyboard, and for that they should be proud.