When Apple released the iPhone, the first mainstream smartphone, in 2007, it revolutionized personal communication by marrying the typical functions of a cell phone (calls and texts) with those of a computer (internet access). Smartphone users can share information and communicate with people anywhere in the world on a device that weighs half a pound. Smartphones are so ubiquitous that analysts predict nearly three-in-four internet users will only surf the web on their phones by 2025. But while smartphones are increasingly popular, not everyone has equal access to them. In 2018, 94 percent of South Korean adults reported owning a smartphone, compared to 13 percent of Tanzanians.