Can SOPA effect the whole world?

I know I could read up more on the subject but I don't have the time or interest to do so. 

What I do know is that SOPA will adversely effect all sorts of information sharing and innocent websites from operating in the way that they currently do and that seems insane.

I understand that if the Senate passes this legislation then there will be a system for shutting down sites which share active GIF files, but what I don't know is whether this is only US sites? 

If it is then it seems to me that that's not the worst thing in the world, after all the world is a mighty small place these days and sites can host themselves elsewhere.

If it's not restricted to the US only then I wonder how this will effect our rights in the UK and the rest of the world; after all US legislation has no power over us and our property. 

Whichever one if the case, it seems clear that some clarity over all internet legislation is going to be needed worldwide if there is ever going to be any control or sense. 

Is this sort of thing happening?
Does anyone know the answer? 
I'd love to know.