PBS will score a broadcast first when American Experience posts its “Earth Days” doc on Facebook before its broadcast premiere, reports the New York Times. Mark Samuels, American Experience e.p., said the showing — which will include PBS underwriting credits — is an experiment. “It’s an opportunity, we think, to engage with a new audience, an audience that we may not be bringing to PBS Monday nights at 9 o’clock,” he told the paper. It’ll hit the social networking site April 11, and TV on April 18. Fans on Facebook will also be able to interact there with Samuels as well as the film’s producer, Robert Stone.