This is how you know Pinterest is going to be huge unless they bungle it big time because no site gets this much notoriety if they aren't doing something so wrong it's right.
Think Napster. Napster changed the entire music industry. Pulled the cork and let that musical genie out of the bottle. I don't think we'd have iTunes, Amazon Music, Pandora, Spotify or much of anything else at this point if Napster and a few other sites hadn't set the stage for the music industry to get a major league wake up call that the future was here and music distribution and sales methods of the past were ancient, had to change, the new paradigm wanted to be set free.
Although I hated what Napster did to copyrights, and I'm not fond of what Pinterest is doing as well, the end result is some very major changes are probably going to happen and problem will happen to benefit the masses.
I'm wondering if people would still pin those images if each image cost from $0.25 to $0.99 or something like that, each auto-billed to their micro-payment accounts?
That's where logic would dictate the image industry has to go based on the transition of the music industry.
The smart entrepreneur would be the first to set up image site to offer a "pinterest buffet" of images for a small fee and quickly sign up a million customers.
I got a great idea for a domain name for that image service, off to register :)