An Open Directory is a web directory that allows users to submit and categorize websites. It is typically maintained by volunteers who review submissions to ensure quality and relevance. This type of directory is often organized hierarchically, making it easier for users to find information based on specific topics or interests. One well-known example of an Open Directory is the Open Directory Project (ODP), which was launched in 1998. Although it is no longer actively maintained, it served as a valuable resource for web users and search engines, providing a structured way to access a wide range of online content.