The interstates the official name, still, is the Dwight D. Eisenhower System of Interstate and Defense Highways--tore down the invisible walls around U.S. towns.President Eisenhower was in favor of building the interstates because he believed that, in a time of war, they would be helpful in moving troops and supplies. But their immediate effect was to make Americans feel that certain doors had been unlocked. With the interstates came an exhilarating sense of freedom: A person could drive anywhere—everywhere--easily and without paying tolls.Suddenly, horizons were unlimited. “Local” didn’t mean quite the same thing it used to. You didn’t have to stay put. Getting away was effortless.And then, later in the 20th century, the Internet came along and with it the promise of the erasure of all symbolic borders. If the interstate highways had allowed physical freedom, the Internet allowed a different kind of freedom, one unprecedented in human experience.It was no coincidence that it was initially referred to as the information superhighway: Seemingly overnight, the knowledge (and trivia and gossip) of the world was available to anyone with a keyboard and a modem; people who had never met and would never meet could communicate as if they were lifelong friends.