AO3, or Archive of Our Own, is a nonprofit online platform that allows users to share and read fan-created works, such as fanfiction and fanart. It was launched in 2009 by the Organization for Transformative Works (OTW) and is known for its user-friendly interface and extensive tagging system, which helps users find specific types of content. The site supports a wide range of fandoms, including popular franchises like Harry Potter, Marvel, and Star Wars. AO3 is notable for its commitment to user privacy and freedom of expression, allowing creators to publish their works without fear of censorship.