If you hadn’t heard of SOPA before, you probably have by now: Some of the internet’s most influential sites—Reddit and Wikipedia among them—are going dark to protest the much-maligned anti-piracy bill. But other than being a very bad thing, what is SOPA? And what will it mean for you if it passes?

SOPA is an anti-piracy bill working its way through Congress…

House Judiciary Committee Chair and Texas Republican Lamar Smith, along with 12 co-sponsors, introduced the Stop Online Piracy Act on October 26th of last year. Debate on H.R. 3261, as it’s formally known, has consisted of one hearing on November 16th and a “mark-up period” on December 15th, which was designed to make the bill more agreeable to both parties. Its counterpart in the Senate is the Protect IP Act (S. 968). Also known by its cuter-but-still-deadly name: PIPA. There will likely be a vote on PIPA next Wednesday; SOPA discussions had been placed on hold but will resume in February of this year.

…that would grant content creators extraordinary power over the internet…

The beating heart of SOPA is the ability of intellectual property owners (read: movie studios and record labels) to effectively pull the plug on foreign sites against whom they have a copyright claim. If Warner Bros., for example, says that a site in Italy is torrenting a copy of The Dark Knight, the studio could demand that Google remove that site from its search results, that PayPal no longer accept payments to or from that site, that ad services pull all ads and finances from it, and—most dangerously—that the site’s ISP prevent people from even going there.

…which would go almost comedically unchecked…

Perhaps the most galling thing about SOPA in its original construction is that it let IP owners take these actions without a single court appearance or judicial sign-off. All it required was a single letter claiming a “good faith belief” that the target site has infringed on its content. Once Google or PayPal or whoever received the quarantine notice, they would have five days to either abide or to challenge the claim in court. Rights holders still have the power to request that kind of blockade, but in the most recent version of the bill the five day window has softened, and companies now would need the court’s permission.

The language in SOPA implies that it’s aimed squarely at foreign offenders; that’s why it focuses on cutting off sources of funding and traffic (generally US-based) rather than directly attacking a targeted site (which is outside of US legal jurisdiction) directly. But that’s just part of it.

…to the point of potentially creating an “Internet Blacklist”…

Here’s the other thing: Payment processors or content providers like Visa or YouTube don’t even need a letter shut off a site’s resources. The bill’s “vigilante” provision gives broad immunity to any provider who proactively shutters sites it considers to be infringers. Which means the MPAA just needs to publicize one list of infringing sites to get those sites blacklisted from the internet.

Potential for abuse is rampant. As Public Knowledge points out, Google could easily take it upon itself to delist every viral video site on the internet with a “good faith belief” that they’re hosting copyrighted material. Leaving YouTube as the only major video portal. Comcast (an ISP) owns NBC (a content provider). Think they might have an interest in shuttering some rival domains? Under SOPA, they can do it without even asking for permission.

…while exacting a huge cost from nearly every site you use daily…

SOPA also includes an “anti-circumvention” clause, which holds that telling people how to work around SOPA is nearly as bad as violating its main provisions. In other words: if your status update links to The Pirate Bay, Facebook would be legally obligated to remove it. Ditto tweets, YouTube videos, Tumblr or WordPress posts, or sites indexed by Google. And if Google, Twitter, WordPress, Facebook, etc. let it stand? They face a government “enjoinment.” They could and would be shut down.

The resources it would take to self-police are monumental for established companies, and unattainable for start-ups. SOPA would censor every online social outlet you have, and prevent new ones from emerging.

…and potentially disappearing your entire digital life…

The party line on SOPA is that it only affects seedy off-shore torrent sites. That’s false. As the big legal brains at Bricoleur point out, the potential collateral damage is huge. And it’s you. Because while Facebook and Twitter have the financial wherewithal to stave off anti-circumvention shut down notices, the smaller sites you use to store your photos, your videos, and your thoughts may not. If the government decides any part of that site infringes on copyright and proves it in court? Poof. Your digital life is gone, and you can’t get it back.

…while still managing to be both unnecessary and ineffective…

What’s saddest about SOPA is that it’s pointless on two fronts. In the US, the MPAA, and RIAA already have the Digital Millennium Copyright Act (DMCA) to request that infringing material be taken down. We’ve all seen enough “video removed” messages to know that it works just fine.

As for the foreign operators, you might as well be throwing darts at a tse-tse fly. The poster child of overseas torrenting, Pirate Bay, has made it perfectly clear that they’re not frightened in the least. And why should they be? Its proprietors have successfully evaded any technological attempt to shut them down so far. Its advertising partners aren’t US-based, so they can’t be choked out. But more important than Pirate Bay itself is the idea of Pirate Bay, and the hundreds or thousands of sites like it, as populous and resilient as mushrooms in a marsh. Forget the question of should SOPA succeed. It’s incredibly unlikely that it could. At least at its stated goals.

…but stands a shockingly good chance of passing…

SOPA is, objectively, an unfeasible trainwreck of a bill, one that willfully misunderstands the nature of the internet and portends huge financial and cultural losses. The White House has come out strongly against it. As have hundreds of venture capitalists and dozens of the men and women who helped build the internet in the first place. In spite of all this, it remains popular in the House of Representatives.

That mark-up period on December 15th, the one that was supposed to transform the bill into something more manageable? Useless. Twenty sanity-fueled amendments were flat-out rejected. And while the bill’s most controversial provision—mandatory DNS filtering—was thankfully taken off the table recently, in practice internet providers would almost certainly still use DNS as a tool to shut an accused site down.

…unless we do something about it.

The momentum behind the anti-SOPA movement has been slow to build, but we’re finally at a saturation point. Wikipedia, BoingBoing, WordPress, TwitPic: they’ll all be dark on January 18th. An anti-SOPA rally has been planned for tomorrow afternoon in New York. The list of companies supporting SOPA is long but shrinking, thanks in no small part to the emails and phone calls they’ve received in the last few months.