This was my thinking as well. On a huge social networking site I would imagine this comes up an awful lot and to have to see those types of images along with other abuses has got to be difficult. I'm also curious if you see enough of them how it changes your mind and if there have been any studies on it.

Fortunately I know you can integrate with that hashing project (I forget what it's called) where they generate a hash for known images of child porn so those can at least be removed automatically but I don't know how much of a percentage that catches.