I think it depends on what you define as "spam". I see many, many, many results pages filled with Facebook pages and Pinterest boards. In many cases, those take up 5 or more spots in the top 10. If I'm doing research for a paper, what good does that do me?
It's not technically spam, it just doesn't belong there.
For that matter, I don't think Pinterest boards should be included AT ALL. A huge portion of those images are stolen. However, even if they were all unique, why is the page with a picture in it showing up in the search results instead of it simply being in the image search? It doesn't make sense.