vBulletin
vBulletin is a proprietary forum software and content management system (CMS) written in PHP and using a MySQL database. It is designed for creating and managing online communities, discussion forums, and bulletin boards with features like user registration, posting, moderation, and customization. Historically, it was one of the most popular forum platforms, especially in the early 2000s, known for its robust feature set and scalability.
Developers should learn vBulletin when working on legacy forum systems, maintaining existing online communities built with it, or for historical understanding of web development. It is useful for specific use cases like migrating data from vBulletin to modern platforms, customizing older forums, or integrating with other systems in environments where it is still in use, though its relevance has declined with the rise of newer alternatives.