"Is Pinterest Illegal?" - Maybe, says noted IP Attorney... good read if you are a Pinterest Participant

But the big problem is that it grabs entire copyrighted works to re-post. This could be hard to overcome, especially as Pinterest starts growing and becomes more of a destination for a greater audience. The more time users spend on Pinterest, one assumes, the less likely they are to click out to other sites. And why click out when you can see the whole picture right there?

via businessinsider.com

Good discussion with an IP attorney.