Thousands of websites entered an Internet blackout today in an effort to show Congress what it could be like if two proposed piracy bills are passed.

Popular sites, including Wikipedia and Google, joined the fight over the Stop Online Piracy Act and the Protect IP Act, also known as "SOPA" and "PIPA." SOPA is a House bill. PIPA comes from the Senate.

The bills are aimed at preventing copyright infringement by foreign websites, but many developers argue that they'll only hurt freedom of speech and shut down sites for Americans.

Paul Levinson, a professor at Fordham University and an expert on media, told News 12 Brooklyn that websites are concerned the bill would give the federal government carte blanche on shutting them down if pirated material is found.

Levinson also says that on a website with massive scale such as Wikipedia, ferreting out all pirated content is very difficult.