Say you have a website that has it's own rules against copyright violations...let's use this site, DeviantArt! And what is considered a "violation of copyright" is lets say a really gray area...like a professional inker who inks someone elses sketch and re-posts it giving full credit to the original pencil artist, but the websites moderators still feel this is copyright infringement! The fact that this is a confusing, to artists, pros, even up and coming artists and everyone in between, gives it enough fuel for the US Government to consider it for you, say it's a violation and ban DeviantArt from not only it's citizens, but from the internet