This is about the 5th or 6th time I've seen something like this.
According to this article, there's a bill being passed through US congress over the next few days to give the US government the power to block or restrict any internet traffic that they choose in an "emergency" - Something similar to the digital economy bill that was passed through UK parliament last year. The government will be able to define what counts as an "emergency" on their own terms, so people are up in arms over the potential threat to free speech and sites like YouTube and Wiki-leaks being shut down.
Personally I think that if governments wanted to shut down the internet for whatever reason and start spying on what people are doing, that they'd have done it already - I mean they're probably doing that now anyway. Restricting the internet too much would be incredibly stupid, since it's such a large part of modern western culture and is an important part of generating revenue for the economy. However, with
articles like this flying around and considering what restrictions China has over its internet, it's no wonder people are nervous.
None the less, there's a petition you can sign against the bill here.