Check out this fabulous blog posting from Kevin Dugan all about consumer-generated marketing (which is a key tenet of our home-grown Active Branding philosophy). "By creating CGMkt, passionate consumers become an extension of a company."
Kevin calls Consumer-Generated Marketing (CGMkt) "the ultimate in authenticity" - because it comes from the customer, not the marketer. He also identifies the dark side of CGMkt - when the customer doesn't like what he/she finds out about a brand.
Tons of great examples (some with creative) - VW Polo, Flickr-vision, Converse, even the much-lauded the Neistat Brothers' iPod "dirty secret" movie that was designed to reveal to the world that iPod batteries aren't quite up to snuff.
Definitely a post (and blog) worth reading (and, commenting on!)