This document discusses Android design and some key challenges. It notes that 480 million people currently use Android devices, which outnumber iOS devices. Popular apps that launch on Android experience huge growth, as Instagram gained 10 million users in 10 days after launching its Android app. However, fewer quality apps are available in Google Play compared to the iTunes Store. Some challenges in Android design include inconsistent hardware, fragmentation, difficulty learning Android, and supporting multiple screen sizes and hardware types. The document provides tips for designing for Android such as understanding its look and feel, building for different hardware, following icon guidelines, and avoiding mimicking elements from other platforms.