Twitter, Facebook, even the biggest social network, MySpace, which was built as a place to market to young people, has been destroyed by the attempts to command

Twitter, Facebook, even the biggest social network, MySpace, which was built as a place to market to young people, has been destroyed by the attempts to commandeer them by marketers. Where in the article does the author prove or even offer evidence that Facebook has been "destroyed"? In what way have the social networks been "destroyed"? Certain Myspace is in flux, but not because of marketeering. Twitter is destroyed? Really?