Designers use these images in photoshop for clients to decide if and which photos to acquire. The watermark is to prevent clients just wanting to steal the images (happens a lot). I think including a url (making the pricing transparent) and including the artist (making it less anonymous) is pretty smart.
Including the photographer's name is the really smart bit. Before, if you used the watermarked image, you were screwing "Getty Images" (a big corporation, i.e. who cares) out of some money. Now, if you use the watermarked image, you're screwing an individual person whose name is right there in front of you out of some money.
