There is a lot that could be done to protest SOPA/PIPA without closing the site.
Other than webapps.stackexchange (which has a small banner), there is no mention of SOPA/PIPA today on any SE site.
There's another question about shutting down StackOverflow/StackExchange, and Joel's answer about SE not owning the content and not wanting to take away access to the Q&As is a good one (and the right decision, to not shut down the site), it's also accepted implying that question is "closed".
So why isn't there at least a banner on all SE sites (seeing as today is about raising awareness to ordinary people, e.g. those who Cook or speak Chinese rather than the usual programmer, tech people who are already against it) linking to somewhere to sign a petition (like on the international Google.com homepage).
Better yet, for the remainder of the day make the background of all SE sites, including the trilogy black, and the text white.
~300 people complained (up-voted the post about it on Meta, in other words they disliked it enough to go to Meta and complain, which frankly is not a lot of effort anyway, and more people up voted Joel's post in favour of the banner) about the banner last time, that's less than 0.03% of Stackoverflow users, and people today are half expecting sites to be closed.