SOPA-- Stop Online Piracy Act. SOPA is supposed to stop people from plagerising(SP?) online, such as art theft, copy-pasting in essays, downloading फिल्में illegally, etc. Many websiteslike Wikipedia temporarily shut down because of SOPA, because it doesn't want America to pass SOPA as a law. There are many who believe SOPA will censor the Internet, when it probably will.
Basically, censoring the internet, like not letting us go on what ever we want. It's shutting down MegaUpload and possibly Google, Youtube, Wikipedia and Facebook...... It's like a 'we have too much freedom, so lets take some away!' kind of thing.