Every hour, Apple sells 16,000 iPhones and 5,400 iPads. Every month, a typical American spends 60 hours online, adding up to a solid month out of every year. Six billion mobile phone subscriptions now exist, the equivalent of 87% of the world’s population. Facebook, founded in 2004, now has 901 million global users; Twitter, founded in 2006, generates 1 billion tweets every 3 days. The Kindle sold an estimated 18 million units in 2011, and e-book sales now surpass paperback sales on Amazon.com.