Participatory Media Theory examines the shift from passive media consumption to active user engagement and content creation. This theory highlights how digital platforms empower individuals to shape cultural narratives and foster collaboration, making users not just consumers but contributors to the media landscape. Historical roots of participatory media can be traced to fan fiction communities, where enthusiasts created and shared their own stories based on popular franchises like Star Trek. With the rise of Web 2.0, platforms like YouTube and Wikipedia enabled global collaboration and democratized content creation. Today, platforms like TikTok exemplify participatory media, where users co-create trends, collaborate on challenges, and generate viral content. This chapter also addresses critical concerns, such as the exploitation of user labor and the concentration of power in platform algorithms. While participatory media democratizes creativity, platform owners often reap financial rewards, raising questions about equity and authorship. This chapter encourages readers to consider both the empowering and problematic dimensions of participatory culture in AI-driven ecosystems.