Spam is not only in the organic search but also in the image-search. I observed a site that steals 140.000 (!) images by hotlinking (also some of my pictures). First the pages itself seems to be "clean". They only set hotlinks to blended search images, and they got a lot of traffic, that sure.
Then they switched the site: on the top there are two porn-ads (it was xslt*us)
I wrote a spam report and posted it an webmasterforum. But it took about 10 days until the site was removed. Hope this gets better...
And: hotlinking is a great problem.