AUSTIN—The knight who invented the World Wide Web came to SXSW to point out a few ways in which we're still doing it wrong.

Tim Berners-Lee's "Open Web Platform: Hopes & Fears" keynote hopscotched from the past of the Web to its present and future, with some of the same hectic confusion that his invention shows in practice. (The thought that probably went through attendees' heads: "Sir Tim is nervous at public speaking. Just like us!")

But his conclusion was clear enough: The Web is our work, and we shouldn't put our tools down.

The British scientist led off with some candy for the audience at the Austin Convention Center, in the form of stories about developing the Web on the "beautiful magnesium box" that was his NeXT workstation. Did you know that the Web's original default port was 2784 because low-numbered ports such as 80, today's default, needed root access?

"The Gopher people had 79, which was so much less cool," said Berners-Lee, drawing knowing laughter.

But the most important part of the Web's origins was its simple open-ness. Before writing a program that could connect to a program on another computer, he said, "I didn't have to ask anybody."

That paved a path to Berners-Lee's points on preserving the Web as a space where any compatible device works. As he put it: "The Web worked because HTML didn't say anything about the platform you were on."

Part of Berners-Lee's sermon involved encouraging people to see the Web as the ultimate app store.

Local apps can easily do things like access a phone's camera, but the mobile Web is catching up with standards to let HTML apps talk to components such as accelerometers, which let programs respond when we tilt or shake our devices.

HTML5 is also pulling in such media capabilities as video conferencing; Berners-Lee pointed the audience to WebPlatform.org, a hub for those efforts.

Web apps, in turn, comply with Berners-Lee's "principle of least power," a rule of simplicity, security and interoperability he defined as "If you're going to transmit something, you should use the least powerful language that you can."

He did not, however, present himself as an opponent of digital locks. During a post-talk Q&A, he defended proposals to add support for "digital rights management" usage restrictions to HTML5 as necessary to get more content on the open Web: "If we don't put the hooks for the use of DRM in, people will just go back to using Flash," he claimed.

Berners-Lee's biggest fear is not a mobile experience dominated by iOS or Play Store apps, but one in which the basic protocols of the Web are eaten away by ISP interference and state surveillance.

Deep packet inspection, for example, allows third parties to "look at all the stuff you're looking up on the Web, and store it, and use it." An Internet provider might employ that to sell ads or charge some sites and services extra; a government could exploit it to slow or disconnect sites it considers harmful.

In all of those warnings, exhortations and technical digressions (such as the virtue of coding in Objective-C, the declining cost of displays that may leave taxis "covered in pixels," the perils of "Turing-complete" languages), however, Berners-Lee didn't emphasize one of the most important features of his invention: the fact that it was also open-source. It fell to introducer John Perry Barlow to make that point.

"One of the more important things that Tim Berners-Lee did was what he didn't do," added the Electronic Frontier Foundation co-founder. "He did not say World Wide Web^TM"