This document discusses how retailers can find and keep valuable customers in a mobile-first world. It notes that 53% of searches and 82% of ecommerce sales will involve smartphones by 2020. Retailers need to focus on understanding how mobile influences total sales, digital influences offline revenue, and finding audiences across channels. Case studies show that optimizing websites for mobile speed can increase conversions by 70% or more. Location-based targeting of mobile users near stores also increased in-store traffic for some retailers. The key is having a holistic audience strategy that uses data to drive action, not restrict opportunities.