Sir Aurthur Conan Doyle killed off Sherlock Holmes in 1893. And all hell broke loose.
When (possibly deranged) Holmes fans reacted in protest, Doyle got back to work on a new Sherlock novel, which explained that the great detective had only faked his death.
Flash forward a few years, and you see the same scene played out over and over again — perhaps most interestingly with the reboot of Veronica Mars, cancelled-TV-show-turned-Kickstarter-funded-movie. Fans love hard, and increasingly, they have the voice and the cash to get what they want out of those who create and control media.
This awesome video from the PBS Idea Channel speculates on a few ways digitally empowered fans could kick media (and, who knows, even government) into high gear.