Mobile apps have become as important as websites for businesses as 4 out of 5 consumers use smartphones to shop. Retailers' apps that offer store maps are five times more engaging for consumers, who spend most of their time in apps for retail (27%), online marketplaces (20%), purchase assistants (17%), price comparisons (14%), and daily deals (13%). Vertical software is designed for a single, narrow market, while horizontal software can be used by different organizations and individuals. Symbian OS is the most widely used mobile operating system, powering 47% of phones, followed by iPhone (17%), BlackBerry (15%), Windows Mobile (14%), Android (5%), and Web OS (2%).