This runs completely contrary to the ideals our country was founded on, including freedom of speech and freedom of press. This isn't just an issue of not being able to access filesharing websites--a blacklist like this could easily be turned into a tool to censor any political defamation, which is essential to our democracy. And this isn't even a slippery slope fallacy, this is for real.
I encourage everyone to sign the petition and if possible, fax or call your congressmen. Also, spread the word among your friends and family!