"It may seem like a dodgy competitive tactic, but broadband network providers could slow down Vonage's service. As subscribers increase their use of latency sensitive and graphic rich . . . traffic, broadband providers could give network precedence to their own revenue-generating services. Unless Vonage pays fees to the network provider, there is no reason the operator should not make the service a lower priority on the network."

This is a bit chilling to Vonage chief executive Jeffrey Citron.

"If that happens in this world, the value of the Internet would instantaneously be massively devalued," he said, because it could happen with any kind of content or application. Although Vonage has seen no actions to degrade its service in the United States, its engineers are suspicious about some complaints it has received from customers in Canada.

Citron said network operators might not choose to impede some services. They could achieve the same thing by having companies pay to have their content or services delivered faster, or first.

Yankee Group analyst Lindsay Schroth considers that reasonable. Why shouldn't the companies that built and run the Internet pipes feeding the home be able to capitalize on their investments? In her view, Internet service providers will begin to provide add-on services, such as higher speed movie downloads, or enhanced online gaming, for additional fees paid by consumers.

Link Hoewing, a Verizon Corp. vice president in charge of Internet policy, said he does not think consumers or businesses would tolerate active discrimination by ISPs. But he said providers need to be able to make money on services beyond the basic connection fee.

Citron said he hates government regulation in general, but this is one case where it might be needed. He said the government should spell out what constitutes a minimum level of broadband service. At least then, he said, Internet users could always receive a baseline level of service, and could pay more to upgrade if they wanted.

The cable industry's trade arm dismisses this as needless regulation, a solution in search of a problem. National Cable Television Association spokesman Brian Dietz said it is hardly in cable's interest to meddle with VoIP quality, because more VoIP users means more broadband customers.

And if customers don't like the Internet service they are getting on cable, they can switch to high-speed DSL from a phone company, he said.

At the FCC, Chairman Michael K. Powell has endorsed the notion of neutrality and challenged the industry to uphold it.

But no rules proceedings are in the works, pending a court case that could change the rules governing cable Internet service.

In the meantime, though, technology marches on.

.Com columnist Leslie Walker is away and her column will resume when she returns. Jonathan Krim can be reached at krimj@washpost.com.