It’s the 25th anniversary of the Web, not the Internet.

To preserve them both, we need to remember the difference.

A note to NPR and other media that have been reporting on “the 25th anniversary of the Internet”: NO, IT’S NOT. It’s the 25th anniversary of the Web. The Internet is way older than that. And the difference matters.

The Internet is a set of protocols — agreements — about how information will be sliced up, sent over whatever media the inter-networked networks use, and reassembled when it gets there. The World Wide Web uses the Internet to move information around. The Internet by itself doesn’t know or care about Web pages, browsers, or the hyperlinks we’ve come to love. Rather, the Internet enables things like the World Wide Web, email, Skype, and much much more to be specified and made real. By analogy, the Internet is like an operating system, and the Web, Skype, and email are like applications that run on top of it.

This is not a technical quibble. The difference between the Internet and the Web matters more than ever for at least two reasons.

First, the Web is a great example of the Internet’s real value: A person can have an idea for how information can be displayed on pages in a browser, and how those pages can include clickable hyperlinks, and how a hyperlink can communicate with another site and cause a page to be transferred, and how all of this can be done without having to set up a central administrative office to make sure the links connect and are acceptable. Tim Berners-Lee didn’t have to ask anyone’s permission, and didn’t have to apply to the Internet Central Management Office to make changes to the network the way he would have had to if we only had the old telephone network. The Internet lets anyone with a great idea change the world. Or, more formally, the Internet is an information transportation system that lets anyone create value using that service.

This is important to remember because the Internet is under deep threat. If we forget the Internet’s essence, we may very well end up with just another paid medium for selling us content. The Internet is in danger of becoming like cable TV because that’s the most lucrative model for the handful of companies in this country that control the majority access to the Internet. If we want to protect the Internet, we have to be clear about the value we’re trying to preserve.

Remembering the difference between the Internet and the Web is also important because it’s not just the Internet that’s under threat. So is the Web. No, the Web isn’t going away. But it’s losing its dominance as the way we interact with the Internet. As we move to mobile devices, apps are becoming more and more important. Most apps run on the Internet, but they generally are not part of the Web. (If you’re not using a browser, you’re probably not on the Web.)

Obviously many apps are fantastic. But they generally fail to have some of the key virtues of the Web.

First, the barrier to creating apps is high, whereas the barrier to putting a page on the Web is low and gets lower every day. The aggregation of apps thus doesn’t represent us — in all our interests and differences — the way the Web does.

Second, apps are not ours, except insofar as we “buy” them (in quotes because we only license them). We built the Web. It is of us and by us. Not so with apps.

Third, apps usually don’t link out of themselves. They try to keep us within their confines. The Web consists of links that send us away from the page they’re on out into a world of related ideas. Of course that world is flawed in important ways, but the generosity of the movement itself — “Here’s a good reason to click away from my page” — is itself worth something.

Fourth, every time you add a page to the Web, you are enlarging a shared world. Every time you add an app to an app store, you’re putting another product on a shelf. That’s fine, but it doesn’t create a richer whole.

I’m not condemning apps. They can be awesome in all the ways that works of humans can be. But as they become more dominant, we should be aware of what they are and what the Web is so that we can remember and preserve the deep values of the Web.

And never more so than on the 25th anniversary of the gift of the Web.