I'm seeing a lot of comments on the web from writers, illustrators and other artists who are scared about Pinterest when it comes to copyright violation. Let me put your minds at ease.
Pinterest users don't "steal" pins. Each pin leads back to its origin. That makes it free advertising. Why post something on your blog if you don't want people to view it? Why offer a poster for sale if you don't want someone to buy it? Why offer a book on Amazon if you don't want people to know about it and buy it? Pinterest can only help creative people. It gives Pinterest users a chance to say, "I love this. You should check this out." Why would creative people fight against that? If you really don't want people to know or talk about your work, you shouldn't publish it on your blog or anywhere else.
Pinterest only lets you pin things from public places on the web. You can't, for example, pin something from Facebook, because that might be private. But what if you're not the person who made your work public? What if someone stole it and posted it to his blog without permission? If so, your problem is with the original blogger, not with Pinterest. If anything, Pinterest might make it easier to find that blogger, because the pin will lead back to his blog.
In short, Pinterest is only a good thing for creative people, particularly visual artists. It makes it easier for people to not only talk about your work and discover it but to immediately access your blog or a place on the web where they can purchase your work.