The Federal Communications Commission's 3-2 vote in favor of so-called "net neutrality" followed an intense debate in Washington pitting backers of online services like Netflix, Twitter and Yelp against big Internet service providers like AT&T and Verizon.
FCC chairman Tom Wheeler said the plan would foster a free and open Internet where broadband services cannot be "gatekeepers" for what is available online.
"The Internet is the ultimate tool for free expression. The Internet is too important to allow broadband providers to be making the rules," Wheeler said ahead of the vote.
Also voting for the plan was Commissioner Jessica Rosenworcel, who said, "We cannot have a two-tiered Internet that speeds the traffic of the privileged and leaves the rest of us lagging behind."
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The plan unveiled earlier this month by Wheeler regulates broadband Internet service providers as "public utility" carriers, revamping the agency's rules struck down by a federal court last year.
In response to a court decision which said it lacked authority, the FCC reclassified Internet service providers as "common carriers" under a 1934 telecom law, while promising to steer clear of rate regulation and other provisions of that law.
The vote comes after the FCC received an unprecedented four million comments, and after President Barack Obama urged the agency to adopt rules enshrining the concept of "net neutrality."
The plan prohibits service providers from blocking lawful content or slowing one service such as streaming video operator Netflix, to support a rival like Hulu.
But the years-long battle may not end with the FCC vote. The ruling is likely to face fresh court challenges, and the Republican-controlled Congress could seek to overturn or modify the regulations.