The tide may be changing in the controversy over SOPA and PROTECT IP (or “PIPA”), the anti-piracy bills that have been making their way through, respectively, the House and the Senate in recent months. Yesterday’s unprecedented 24-hour global blackout of the English Wikipedia site in protest of the legislation and the new enforcement powers it would create has acted as a lightning rod for public attention. In concert with Wikipedia, Google ran a “censored” version of its logo on its home page yesterday, with a plea to users to contact their legislators, and many other popular sites displayed blacked-out screens together with information about the bills. Wikipedia reports today that SOPA was featured in a quarter-million Tweets per hour during the blackout.

Yesterday’s high-profile online activism follows months of public debate about SOPA and PIPA, which critics fear could chill online speech and destabilize the architecture of the Internet. While the legislation still has many vocal supporters – the Motion Picture Association of America’s chairman, former senator Chris Dodd, called the blackouts “stunts that punish users” – the ranks of opponents seem to be growing, and now include such strange bedfellows as the ACLU and the Tea Party. Ars Technica reports that 18 senators, seven of whom are former co-sponsors of PIPA, announced their opposition to the bill yesterday.