Tomorrow’s previously scheduled markup for the Stop Online Piracy Act, which critics claim would institute Internet censorship in the name of policing copyrights and could have a deleterious effect on the Internet’s architecture, has been cancelled. The announcement was first leaked by Rep. Darrell Issa, an opponent of SOPA, on his Twitter feed.

A note on the House Judiciary Committee’s website claims that the markup was “postponed due to (the) House schedule.” And indeed, the House does not appear to be in session tomorrow. However, this continuation of the markup was scheduled late last week, at a time when the House was already not planning on being in session. So that seems like a convenient excuse to me. In reality, the opposition that has been growing against SOPA over the past few weeks probably led to the cancellation.

It’s not entirely clear what this means for the bill. As Cory Doctorow muses, the majority could be setting up a negotiation session, or they want to hold off for a month or so until Congress resumes, hoping that the activist movement will have dissipated by then. I don’t think that’s likely. The activist hub for anti-SOPA actions has been aggressively rolling out new supporters and driving phone calls and emails. I’d be surprised if they just forgot about things in a month. Plus, this puts the bill into 2012, an election year, which should make it more difficult to pass.

The Motion Picture Association of America, which supports SOPA and has been lining the pockets of supporters in Congress, sent out a comical justification for the proposition that interfering with the Internet’s architecture would not represent any threat to the core of the Internet itself. As proof, it literally cited the kind of censorship activities that governments have undertaken in China, Iran, the UAE, Armenia, Ethiopia, Saudi Arabia, Yemen, Bahrain, Burma, Syria, Turkmenistan, Uzbekistan, and Vietnam. Quite the company the MPAA wants the US to keep.

Activists will have to stay strong, but they have won a round here.