If you've been living under an Internet-free rock the past couple of weeks, you might have managed to miss the steady drumbeat of opposition to HR 3261, the so-called Stop Online Piracy Act (SOPA). Then again, if you've been living under an Internet-free rock, you've already had a preview of what we're facing if SOPA goes into effect.

I'm exaggerating a little, but not by much. We've covered SOPA earlier this week and the EFF's efforts to rally opposition to the bill. But today is American Censorship Day and a hearing for the bill in the U.S. House that's stacked in favor of the bill.

AmericanCensorship.org has pulled together an infographic that explains in very basic terms the services and sites that are at greatest risk from SOPA. This includes Facebook, Reddit, The Onion Router (TOR), Alternative DNS services and a lot more. DNS blocking, which is what the proponents of SOPA want to use to block any site that might be considered infringing – before a court has even ruled – is also used in China, Iran and Syria to try to block political sites.

American Censorship Day is organized by Mozilla, the Free Software Foundation, PublicKnowledge, Demand Progress, the EFF, Creative Commons and a number of other organizations. I happened on the page thanks to a "censored" logo in the Disqus dashboard while moderating comments. If you'd like to get your own "censored" logo, or if you want to learn a bit more, head over to AmericanCensorship.org.