If all non-US citizens that use the English Wikipedia had US citizen friends they could engage politically, US politics would look vastly different already.
But SOPA would affect us english speaking non-US people too, so raising awareness in the rest of the world is a good idea. We should be putting pressure on our own governments to a) not pass a SOPA-like law themselves and b) to not support the US in this, for example, Spain shouldn't cave into US pressure to pass a similar law.