This is relevant to two posts: - Yesterday's on the value of being a first mover, specifically on Pinterest; and - Porsche moving users between their Facebook and Pinterest pages
Well here's another good examples: Harrods is allowing fans to help design their retail windows using Pinterest mood boards.
Clever: It's on brand. It's effectively free marketing. It drives Pinterest activity far beyond the winner. And it blends users across Pinterest and Facebook - both from the cross-promotion and Pinterest's opengraph integration.