This document discusses strategies for retaining mobile users. It notes that by 2018, smartphone penetration in the UK will reach almost 100% and that people spend more time on their mobile devices than watching TV. The document then provides tips for engaging users such as making a great product, understanding user habits and context of use, avoiding churn, segmentation and personalization, listening to feedback and iterating. It emphasizes the potential of push notifications for driving user engagement and retention.