I maybe see a film in an actual movie theatre a handful of times each year. I don't like movie theatres - ticket prices are expensive, the seats are uncomfortable, the internal temperature is typically too cold and the concession food is garbage. But I did go out to see An Inconvenient Truth and it was well worth the price of (matinee) admission. Global warming isn't an unknown of topic in my social/employment circles, but the data presented and the potential implications were horrifyingly new to me. As someone who lives within the 20 feet from sea level range, it's somewhat difficult to imagine what life would be like if my city no longer existed.
I do wonder though if this film will succeed in significantly impacting behavior. The worst perpetrators of global warming - on either an individual or corporate level - aren't going to see the film, aren't going to read the book, and aren't going to change their practices one bit unless a higher authority compels them to do so.
But I don't want to be a total pessimist, so I've committed myself to being more vigilant about recycling and will abstain from using the clothes dryer this summer. The film contends that without intervention, significant environmental changes will happen within the next fifty years. Many of us will still be alive during that time. Do we really want to wait around to see if it "comes true"?