Chris and Matt have already explained at length the danger in PZ's unintentional promotion of Ben Stein's Expelled. What's also interesting to consider is the strategy employed in the 'super trailer', which utilizes many subtle techniques that have proven successful in the social marketing of ideas to large audiences over time. They include a call to question authority, hints of a 'big science conspiracy', unspoken references to abortion through imagery, inadequate interpretation of Darwin's evolution, spooky music, and a seemingly reputable purveyor in Stein. I still don't understand the photo of Auschwitz, but maybe you need to see the full length feature to get the Darwin-Nazi connection.