Fairly sure an ISP can block anything they want. SOPA just gives them a list of additional sites they have to block.
http://webcache.googleusercontent.com/search?q=cache:BUzX5jpdk8cJ:megaupload.com/+
Holy stuff.So many download links were just nulled.I find that kind of weird, it gets shut down but The Pirate Bay has never been shut down...