Savvy businesses know to go where the customers are, and increasingly, those customers are spending time on mobile. In 2018, Statista projects there will be 236 million smartphone owners in the U.S., a population that will grow to 257 million by the end of the decade. Those with smartphones, tablets, and other mobile devices are downloading apps at a rapid rate. App downloads, which totalled upwards of 90 billion last year, increased by 15% from 2015 to 2016, and the time users spent on them grew by 25%.