Quote from the Avaaz website:
Save The Internet!
Right now, the US Congress is debating a law that would give them the power to censor the world's Internet -- creating a blacklist that could target YouTube, WikiLeaks and even groups like Avaaz!
Under the new law, the US could force Internet providers to block any website on suspicion of violating copyright or trademark legislation, or even failing to sufficiently police their users' activities. And, because so much of the Internet's hosts and hardware are located in the US, their blacklist would clamp down on the free web for all of us.
The vote could happen any day now, but we can help stop this -- champions in Congress want to preserve free speech and tell us that an international outcry would strengthen their hand. Let’s urgently raise our voices from every corner of the world and build an unprecedented global petition calling on US decision makers to reject the bill and stop Internet censorship. Sign now and then forward as widely as possible -- our message will be delivered directly to key members of the US Congress ahead of the crucial vote.
sing the petition here
Edit: Here is some more information about the bill this is trying to stop: