U.S. lawmakers appear to be abandoning their support for controversial copyright legislation after one of the biggest online protests in history.

Thousands of websites – ranging from social-networking sites to blogs to online pharmacies – went dark on Wednesday to protest against two pending pieces of legislation aimed at countering online piracy by drastically re-engineering the way the Web works within the United States.

As a result of the protest, some of the most popular sites in the world, including Wikipedia and Reddit, became difficult or impossible to access. Instead, the sites carried notices informing visitors of the organized protest against two bills – the Stop Online Piracy Act and the Protect Intellectual Property Act – currently before the House and Senate, respectively.

Initially coasting well below the public radar, the two bills have become the focal point of a battle between traditional content producers in the movie, music and TV industries – which have decades of experience in Washington lobbying – and the emerging technology behemoths looking to flex their muscles by leveraging their massive user bases.

Even though the biggest corporate opponents of SOPA and PIPA – Google, Facebook and Twitter, among others – didn’t go dark on Wednesday, the digital blackout appears to have prompted several key legislators to drop their support for the bills, in the process altering the political landscape and making it far less likely either bill will pass smoothly.