It's not Social Media that's changing the video, film, and many other creative industries. Computers and the Internet are doing that. Social Media is a tool that people are using to try and reinvent creative mediums: people no longer buying music [leads to] labels no longer promoting and grooming new acts [leads to] acts having to do it themselves.
Social Media - like the Internet that came before it [you're being ironical, aren't you?-Ed]- provides new ways for individuals to market to people. How successful any individual effort will be really depends upon how good they are at marketing - and also, to a great extent - how lucky they are. Having the right product is maybe half the battle; being at the right place at the right time can be just as important.
But then, that's how it always was. The difference now is that many people are taking over the promotion themselves. You no longer have to sell yourself to the gatekeepers; you have to sell yourself to everyone. And as Laura Miller at Salon asks, if you have to be good at selling yourself to get your creative work out to the audience, is that necessarily a good thing?
MasteringFilm: What Social Media Really Means To The Film Industry
Salon: Author, sell thyself