Google recently also criticized Facebook for similar reasons. In early November, such as Gmail unless the site also allowed Google access to similar data. Notably, Facebook has never allowed Google to access its user contact information, although Facebook users can import Gmail contact data.

Facebook managed to work around Google's change, and in response, Google now warns users that if they export their data to Facebook, they won't be able to get it out.

Such closed worlds are also created when companies such as Apple decide not to use open standards. Berners-Lee gives the example of iTunes, where he says that although songs and videos use open URLs, their addresses begin with the proprietary "itunes:" rather than the open "http." That means users can't make a link to information in iTunes and send it to someone else. "You are no longer on the Web. The iTunes world is centralized and walled off. You are trapped in a single store, rather than being on the open marketplace," Berners-Lee wrote.

The trend toward building smartphone apps, rather than Web apps, leads to similar problems, he said. Material in native apps is "off the Web," meaning that users can't bookmark it or link to it.

Such trends lead to similar scenarios as the walled gardens that were popular in the 1990s, such as AOL, that ultimately proved unsatisfying to users, he said. Those environments, even if they are easy to use, "can never compete in diversity, richness and innovation with the mad, throbbing Web market outside their gates," he wrote.