Facebook Audience Insights is a powerful tool provided by Facebook that allows marketers and advertisers to gain valuable insights and data about their target audience. It provides detailed demographic information, interests, behaviors, and preferences of Facebook users, helping marketers understand their audience better and make informed decisions when creating targeted advertising campaigns. This tool enables marketers to analyze and segment their audience based on various criteria, such as age, gender, location, interests, and purchase behavior, ultimately helping them optimize their marketing strategies and reach the right audience effectively.