Traditional big media firms have contributed more than $5 million to the sponsors of the Stop Online Piracy Act, with California Democratic Reps. Howard Berman and Adam Schiff as the top recipients.

The bill, known as SOPA, would strengthen and extend the penalties for online copyright violations, and could force websites hosting pirated content to come down or prevent search engines from sending users their way. Legacy media companies stand to benefit if there's less unlawful movement of their content on the web, like pirated movies and songs for download.

Some of the nation's top tech companies — Facebook ...