This document discusses defining target audiences and developing personas to better understand them. It explains that personas simplify audiences into groups with demographics, constraints, and needs/wants. The persona development cycle involves identifying roles, listing needs/triggers, and creating messaging objectives for each persona. There are three types of personas: those with needs the product satisfies, ability to purchase, and interest in new products. Specifying personas further involves adding traits to increase response. The level of specificity should balance information costs and message persuasiveness. Understanding where audiences are online and what they discuss is also important for social media marketing.