The EFF’s View (Electronic Frontier Foundation)
A Reddit Summary
We wouldn’t even have xkcd!

Basically, SOPA completely undermines everything the Founding Fathers and their successors worked for, violating freedom of speech, press, and, indirectly, assembly. This bill is fundamentally flawed. It would affect every country in the world. I wish pirates would stop stealing just as much as you do, but this violates just about every freedom we have. A lot of the content on this blog is in violation of that bill. YouTube, Flickr, Facebook, Twitter, just about every website is in violation of that bill. If there’s a way to stop pirates, this isn’t it.