Recently, as I was browsing the shelves of my local used book store, I realized that I was engaged in "piracy" of exactly the same kind as what the legacy entertainment industry has slammed as a scourge so terrible that it is worthy of giving up our online freedoms to protect. This is what SOPA is supposed to protect us from.
Not one of the books or videos on these shelves would share one cent of what I paid with the author. Which is exactly the "moral panic" we're being sold about copies on the internet.
But in fact, if you feel you need to read what somebody has to say, while simultaneously avoiding paying them anything (because the author or publisher is a sex offender, a racketeer, or, say, Disney), then buying a copy from a used bookstore is one way to act out that ethical intent. Another way is to voluntarily pay a "tip" or "donation" to an online author who you do like, but whose work is almost entirely freely available online without paying (obligatory shameless plug for my book). Or, if that's a little too difficult, you can just choose to buy a copy of the work from a channel that shares profit with the author.
Many people will tell you why SOPA is bad and how: it will promote censorship, it will break the internet, it will put the United States on par with oppressive regimes, and in the end, it won't actually work.
But what I want to say is this: we don't need it. It's an attempt to solve a business problem of a changing market which already has solutions by making laws to protect the currently wealthy publishers, who haven't done a very good job of supporting artists anyway.