Yes there is a site out there coming to our attention, polyvore.com

The sites intention was for people to 'clip' images from shops of fashion items they like and create a 'set' with these clips (collages). The clips are supposed to have links back to the original shop thus encouraging people to buy. This is how they justify the taking of copyrighted images.

Now the site is being used more for just creating collages as pieces of art and users are not limiting themselves to shops and catalogs. google images and of course dA is becoming a rich source of images for these people. Yes this is image theft and goes by the theory 'its easier to ask forgiveness than permission'

It seems they run off the basis music file sharing sites used to do, their original intent may have been ok, but they are not responsible for misuse. When a claim comes up they handle it. They have been around since 2007 but maybe with this additional use and scrutiny by copyright authorities something may change (I hope).

If you do find your image there being used and you want it removed they do have a nice little form (basically a DCMA) for you to fill out and they promise a response with in one day.

Form: [link]

More info on their copyright policies [link]