http://www.thefancy.com/,
http://weheartit.com/,
http://ffffound.com/There are hundreds of sites like Pinterest. It's fundamentally how the internet works. A free exchange of information. If you don't want your copyrighted content on Pinterest, file a DMCA notice.
imgur.com has more traffic (even more traffic than reddit) and almost no way to attribute content, yet no one is crying foul; all while imgur brings in significant amounts of money for other people's content. I don't see the difference.
To take the nonsense further... Reddit makes tons of money providing links to other people's content (usually linked through imgur with no attribution). Google makes billions off advertising against other people's content, search results and copyrighted images. Where do you draw the line in the nonsense?