I don't think going dark completely is good, for that very reason. That wouldn't stop Google from making a very prominent display of their argument against SOPA

I don't think going dark completely is good, for that very reason. That wouldn't stop Google from making a very prominent display of their argument against SOPA/PIPA -- placing the message on the homepage, featuring it on SERPs, etc. I think if Google just put the message at somewhere on the homepage, it would have a profound effect, given how bare the Google homepage is. That, of course, wouldn't get the message across to the many people who use built-in search in browsers and other such methods of accessing SERPs.