This document discusses key concepts for identifying and segmenting publics: 1. Key publics are groups that are affected by or can influence an organization, share common concerns or goals, and can be defined demographically or by roles. 2. Publics can be directly reached or influenced through intervening publics like media and opinion leaders using two-step flow theory. 3. To identify key publics, organizations should understand their demographics, psychographics, relationships, opinions of the issue and organization, and how publics can help achieve objectives. 4. Segmenting publics involves understanding their knowledge, involvement, and constraints to determine if they are active, aroused, inactive, or non