Stop Online Piracy Act (SOPA or H.R.3261)
SOPA primarily seeks to fight "rogue websites," and would make unauthorized streaming a felony. This means even recording and uploading a video of yourself playing a video game could be punishable by law. Moreover, the act would remove provisions from the Digital Millenium Copyright Act, meaning that sites with mostly user-contributed content, like YouTube, would be held accountable for ensuring that their users do not post infringing material. So, if a corporation chose to, instead of users simply being forced to take down any videos for copyright infringement, they could be held liable and punished accordingly.
PROTECT IP Act (Preventing Real Online Threats to Economic Creativity and Theft of Intellectual Property Act of 2011 or S.968)
This act would remove the "safe harbor" provisions of the Digital Millenium Copyright Act, which grants websites immunity from prosecution for hosting infringing content, as long as they quickly remove said content. Under this proposed law, many online communities--including Facebook, Twitter, and YouTube--would have to censor users or get shut down, and individuals who post copyrighted work could be imprisoned for up to five years.
To read more about the bills and contact your representatives, go to Tumblr.