The Internet—as a few highly-visible prognosticators see it— is undergoing a radical shift toward a more closed, app-driven environment. Facebook, Apple, and media giants are all building "walled gardens" to control users' experiences, causing some considerable hand-wringing over the demise of the browser-dominated, free-wheeling Internet days.

The latest to make such a prediction is the man credited with inventing the Web itself: Tim Berners-Lee. In a Scientific American essay, he argues that if current trends continue unchecked, the Web will devolve into walled-off, "fragmented islands" where information cannot flow freely. While Berners-Lee notes that "by no means" is the Web "dead," there needs to be a consensus in the scientific community and the press to "preserve" the openness that we have gained and "benefit from the great advances that are still to come."

Social-networking sites—and Facebook in particular—are exacerbating the problem. The more information is entered into Facebook, "the more you become locked in," he writes. "Your social-networking site becomes a central platform—a closed silo of content, and one that does not give you full control over your information in it. The more this kind of architecture gains widespread use, the more the Web becomes fragmented, and the less we enjoy a single, universal information space."

The danger of these Web giants, as he sees it, is that one search engine, social-networking site or browser "gets so big that it becomes a monopoly, which tends to limit innovation." And for those who argue that closed systems are "just fine," he reminds readers of what America Online was like in the '90s:

Some people may think that closed worlds are just fine. The worlds are easy to use and may seem to give those people what they want. But as we saw in the 1990s with the America Online dial-up information system that gave you a restricted subset of the Web, these closed, “walled gardens,” no matter how pleasing, can never compete in diversity, richness and innovation with the mad, throbbing Web market outside their gates. If a walled garden has too tight a hold on a market, however, it can delay that outside growth.