Like Instagram, Pinterest was never going to be a free ride forever—you're not paying for it with money, so you'll pay with your eyeballs instead. Here come the advertisements, and you all better start buying some tote bags and twine balls real fast.
The new sponsored pinnings look a lot like sponsored stuff on Tumblr: just like everything else, only with the addition of tiny text. At least there's an informative pop-up explanation of why you're seeing sponsored items, for now.
But again! This is the way it has to be: investors say Pinterest is worth $2.5 billion precisely because it could be the most powerful, manipulative catalog ever assembled. It starts now.