This was not the way the internet was supposed to go. At its deepest technical level, the internet was designed to avoid the central points of control that now command it. The technical scheme arose from an even deeper philosophy. The designers of the internet understood that communications networks gain new powers through their end nodes — that is, through the new devices and services that plug into the network, rather than the computers that manage traffic on the network. This is known as the “end-to-end” principle of network design, and it basically explains why the internet led to so many more innovations than the centralized networks that came before it, such as the old telephone network.

The internet’s singular power, in its early gold-rush days, was its flexibility. People could imagine a dazzling array of new uses for the network, and as quick as that, they could build and deploy them — a site that sold you books, a site that cataloged the world’s information, an application that let you “borrow” other people’s music, a social network that could connect you to anyone.

You didn’t need permission for any of this stuff; some of these innovations ruined traditional industries, some fundamentally altered society, and many were legally dubious. But the internet meant you could just put it up, and if it worked, the rest of the world would quickly adopt it.

But if flexibility was the early internet’s promise, it was soon imperiled. In 2003, Tim Wu, a law professor now at Columbia Law School (he’s also a contributor to The New York Times), saw signs of impending corporate control over the growing internet. Broadband companies that were investing great sums to roll out faster and faster internet service to Americans were becoming wary of running an anything-goes network.

Some of the new uses of the internet threatened their bottom line. People were using online services as an alternative to paying for cable TV or long-distance phone service. They were connecting devices like Wi-Fi routers, which allowed them to share their connections with multiple devices. At the time, there were persistent reports of broadband companies seeking to block or otherwise frustrate these new services; in a few years, some broadband providers would begin blocking new services outright.

To Mr. Wu, the broadband monopolies looked like a threat to the end-to-end idea that had powered the internet. In a legal journal, he outlined an idea for regulation to preserve the internet’s equal-opportunity design — and hence was born “net neutrality.”