CNET reports: The Internet’s most popular destinations, including eBay, Google, Facebook, and Twitter seem to view Hollywood-backed copyright legislation as an existential threat.

It was Google co-founder Sergey Brin who warned that the Stop Online Piracy Act and the Protect IP Act “would put us on a par with the most oppressive nations in the world.” Craigslist founder Craig Newmark, Twitter co-founders Jack Dorsey and Biz Stone, and LinkedIn co-founder Reid Hoffman argue that the bills give the Feds unacceptable “power to censor the Web.”

But these companies have yet to roll out the heavy artillery.

When the home pages of Google.com, Amazon.com, Facebook.com, and their Internet allies simultaneously turn black with anti-censorship warnings that ask users to contact politicians about a vote in the U.S. Congress the next day on SOPA, you’ll know they’re finally serious.

True, it would be the political equivalent of a nuclear option–possibly drawing retributions from the the influential politicos backing SOPA and Protect IP–but one that could nevertheless be launched in 2012.

“There have been some serious discussions about that,” says Markham Erickson, who heads the NetCoalition trade association that counts Google, Amazon.com, eBay, and Yahoo as members. “It has never happened before.”