In the end, the reason that SOPA exists is because corporate interest groups are literally writing our laws. If you stop SOPA it's like cutting off the top of a dandelion - as long as the roots are in the ground it will just come back.
Lobbyists and persistent and clever, they will slip the laws they want in as a rider on a budget bill, or they'll just keep trying until the opposition movement peters out.
We have to attack the cause.
A very similarly evil act, the Research Works Act (RWA) is moving forward. In brief, the RWA makes it illegal for the government to require that researchers that receive government funding make their results available for free (eg. on the internet). The RWA was written by the AAP (American Association of Publishers), which is made up of the IEEE and ACM and all the usual suspects, who want to have exclusive rights to research paper copyrights.
It should be noted that even before the RWA has passed, we currently have pathetically weak open access to research requirements. Only research that receives direct grant funding from something like the NIH is required to supply open access. But almost all research is actually government funded, because the researchers are paid by colleges, and the colleges get government funding (and of course all research is based on past research, which is a public good, etc). But this type of funding does not require the documents to be open access. So, first of all :
Colleges : require all of your professors' publications to be open, NOW!
Apparently Harvard has sort of done this but not many others have followed suit.
(colleges also have no right to own patents or create public/private partnerships for business development of professors' work. That research is owned by all of us. But that's another topic...)
The IEEE and ACM's standard publication terms gives them exclusive ownership of the copyright, which really they have no business in getting, since their contribution to the work is near zero (eg. peer review is done by unpaid volunteers, they provide almost zero paid editing, etc.; they aren't like a book publisher that actually does something).
Authors : stop publishing your papers in works that take your copyright! Make all your works "open access" only!
Pick an Open Access Journal instead.
Some of the blog posts I've read about the RWA have been very naive in my opinion ; they seem to think that the scholarly organizations like the ACM or IEEE are better than the RWA and aren't specifically the people behind it. I think it should be absolutely clear by now that the RWA is exactly in line with the sleazy character of these usurious organizations.
Scholars : quit the ACM and IEEE right now.
It's very simple, these publishers are bad for science, and they serve no purpose at all in a world where the internet is the most important form of publication.
But more generally it's just another case of corporations writing the laws and pushing an agenda that's bad for America. We may stop SOPA and RWA, but it will just happen over and over again until we fix the problem. Stop corporate personhood. Make lobbying illegal. Make it illegal for corporations to write laws.