Film production companies don't usually have missions beyond the obvious one of making money. But two relatively new companies - Participant Productions, whose recent movies include "Syriana" and "North Country," and Walden Media, a producer of "The Chronicles of Narnia: The Lion, the Witch and the Wardrobe" - have overt social purposes and activist campaigns attached to their movies. The old Watergate-era dictum "Follow the money" has suddenly become relevant to moviegoers. Caryn James reports (free subscription required to view full article).