Annual global advertising spend on mobile devices is expected to reach $105 billion by 2019, up from an estimated $51 billion this year, as an attitude shift causes more brands and retailers to use mobile as a core channel for consumer engagement, according to a Juniper Research study. The research, “Digital Advertising: Online, Mobile and Wearables 2014-2019,” argues that the ability of smartphones to deliver targeted, personalized and timely advertising – allied to millennials’ fondness for multitasking on mobile – means that mobile ads offer both high visibility and high response rates. The results point to the power of tech-savvy millennials to drive an attitudinal change among brands and retailers due to their embrace of a mobile-centered lifestyle.