Americans love cars so much that we pioneered many of the first cars cheap enough for middle-class consumers, designed vast suburban expanses around the car, built much of the Midwest on producing and exporting cars, spent billions bailing out those auto producers, and today boast by far the world's highest per capita rate of car ownership. But The New Republic's Bradford Plumer says that Americans are becoming less enamored with owning and driving a car. He cites two reasons: concerns about energy and, interestingly, social media technology:

There's growing evidence that young people, for one, are less enamored of driving than their parents were. In 1976, three-quarters of all 17-year-olds had drivers' licenses. By 2008, that was down to 49 percent. And, in a recent survey by Zipcar, the car-sharing company, a full 67 percent of 25- to 34-year-olds said they would prefer to drive less, especially if alternatives were available (Zipcar's not a disinterested party here, but other surveys have yielded similar results). The shift in mood partly reflects worries about the environment and the price of gas. But there also seems to be a technological aspect, too. Once upon a time, newly licensed teens would pile all their friends into their new used car and drive around aimlessly. Nowadays, teens can socialize via Facebook or texting instead—in the Zipcar survey, over half of all young adults said they'd rather chat online than drive to meet their friends.
Plumer also chronicles the backlash against those who advocate going without a car, which backlash has stretched from 1970s "car revolts" to the current Tea Party skepticism of smart growth policies meant to foster urbanized communities where cars are less necessary. But whether or not public policy accounts for the growing changes, it appears that cars may become less popular.