You should be able to stand anywhere in the world, and foursquare will tell you something to do nearby.
—DENNIS CROWLEY, Cofounder, foursquare
On October 22, 2010, NASA astronaut Douglas Wheelock became the first man to “check in” from space. Back on Earth, 220 miles below, millions of people did the same—at the rate of 23 times per second. They checked in to restaurants, bars, stores, hotels, gyms, and other places in every city, country, and continent. What were they doing?
Less than 10 days later, on October ...