When Vannevar Bush, Franklin D. Roosevelt's chief scientific adviser, sat down in 1945 to write a magazine article about the future, he had no idea what he was beginning. Bush's vision of a desktop computer that would contain all of human knowledge inspired the scientists who built the Internet. In the early 1990s, when a British computer programmer devised the World Wide Web and an Illinois student invented an easy-to-use Web browser, the Internet...