The document provides an introduction to mobile design for designers. It discusses key considerations for whether to build a mobile website or app, including user needs, marketability, content requirements, and costs. It also lists 11 things web designers should know before designing for mobile, such as using mobile analytics, understanding user contexts, and designing based on rules rather than pixels. The document explains that mobile is defined by being interactive, personal, and the new normal way technology is accessed. It encourages joining an online mobile design patterns community.