Simple. To show the US Congress how it affects the Common Man, who is very connected to the Internet. Some of the ways are:
If SOPA/PIPA passes, all of that would be gone.
Many social network sites, such as Facebook and Gaia Online use images that don't have a copyright (due to age or other similar situations) on their sites. Many of these images are created by the fans of movies and/or TV shows.
If SOPA/PIPA passes, the social networks would also vanish.
Many people would show that they are addicted to the Internet as they start to show withdrawal symptoms. Businesses would lose money due to loss of online sales. Others will lose their jobs as maintaining the machines that power the Internet (such as Earthlink) need less people to do the work.
This site, along with many other personal and business sites, would also disappear as Dreamhost, a web hosting site, would lose almost all its customers.
So join a protest against these two bills, or call your Congressman/woman and tell them to kill SOPA/PIPA while it is still in Committee. (Not sure how our government makes laws? Go search YouTube for "I'm Just a Bill" from Schoolhouse Rock.) Tell them that SOPA/PIPA is UnConstitutional as it goes directly against the First Amendment.