WHEN I was first learning about the Internet, one of the most difficult concepts to grasp was that it belonged to no one. There was no central authority managing the network. Nobody owned or controlled it. Not even Bill Gates. And because it belonged to no one, it belonged to everyone, and millions of Web sites flourished, the small growing right alongside the giants. In this hothouse environment, small, nimble companies quickly grew into giants in their own right to challenge traditional, Old World corporations.

This egalitarian approach also gave rise to an unprecedented exercise of free expression, where anyone could make his voice heard by thousands or even millions, by creating a blog and going online.

All that’s going to change, if large American carriers have their way.

In the United States, the big telecommunications carriers AT&T, Verizon and Comcast want to start charging large, “first-tier” online companies such as Yahoo, Google, eBay and Amazon more money for a premium service that will ensure their pages get to you faster. On the other hand, smaller companies and individual bloggers who can’t pay for the premium service will have to take their chances with the regular service and hope visitors will still be able to find their way to their Web sites.

This pay-to-play approach would be akin to the carriers dividing the Internet into business class and economy, with those who can afford it getting better food and service, more comfortable seats and all the perks, and those who can’t getting cramped seats and crappy meals.

The principle under attack is called network neutrality, and it’s based on the notion that the network doesn’t care about what kinds of bits are being transported or who is sending them; it will move them to their destination through their broadband pipes with the same speed and efficiency, without discrimination.

The issue is particularly hot in the United States, where the carriers say a tiered service would allow them to fund new broadband investments, while critics of such an approach are lobbying the US Congress to pass laws to protect network neutrality.

Robert Reich, professor of public policy at the University of California at Berkeley and former labor secretary in the Clinton administration disagrees.

“The pipe companies claim that unless they can start charging, they won’t be able to invest in the next generation of networks,” he says. “Well that’s ridiculous. They’re already making lots of money off consumers connected to the Internet. They just figure they can make more money charging the big content providers for the best service.”

Tim Berners-Lee, the inventor of the World Wide Web, has also spoken out in favor of network neutrality and against the idea that “if I want to watch a TV station across the Internet, that TV station must have paid to transmit to me.”

The forces lining up on both sides of the debate are formidable.

Aligned with the giant carriers are their big network equipment suppliers such as 3M, Cisco, Corning and Qualcomm. The cable companies, too, oppose legislation to ensure network neutrality.

Ranged against these companies are the big online players, Microsoft and the Save the Internet Coalition (http://www.savetheinternet.com), which groups more than 700 organizations from the leftwing Moveon.org to the rightwing Gun Owners of America.

For now, as Berners-Lee observes, network neutrality is a US-only issue. But the United States is such a dominant force on the Internet that what happens there will clearly have an impact elsewhere. For that reason alone, those of us who care about keeping the Internet an open marketplace of ideas ought to support network neutrality and hope that battle is won in the United States.