I can still remember when Trip Advisor brought in badges. A lot of the main contributors left shortly afterwards. But as was pointed out, those people weren't the ones bringing in the revenue to the site, so they didn't really care, the badges were to engage those masses not the main contributors.
But you will have noticed that the site stopped being useful shortly afterwards as well, I certainly stopped trusting any of its content. Let's hope the same thing doesn't happen here.