One of the reasons that "The Dark Knight" achieved so much success was the brilliant viral marketing campaign that brought "Why so serious?" into the popular culture vernacular way before the film even hit theaters. Now with a third Christopher Nolan-helmed "Batman" movie officially announced, it's a virtual certainty that fans are in store for more viral marketing - but when it comes to the Caped Crusader, such tactics existed long before "The Dark Knight."

In 1943, Columbia Pictures released a 15-chapter "Batman" theatrical serial starring Lewis Wilson as the world's greatest detective and Douglas Croft as his boy wonder sidekick. In order to get the public into theaters for the serial, Columbia gave away cardboard Batman masks to promote the project and drive business. These masks are extremely rare now, as Anonymous Works notes that one such mask recently sold for $3,597.03.So if you have any swag left over from the marketing campaign for "The Dark Knight," you would be wise to keep said swag very safe. It's also something to keep in mind when the ad campaign goes into high gear on "Batman 3." If these 1943 masks selling for almost $4000 are any indication, there's no telling how valuable today's marketing tools will be sixty years from now!

[Link via Brian Denham]