Citadel is a different kind of messaging and collaboration platform. While others focus on automating business processes, Citadel focuses on connecting communities of people together. Users love Citadel because it's software that helps them work, play, stay in touch... without calling attention to itself.

A Citadel system is made up of containers called "rooms." A room may be used as an email folder, a discussion forum, a real-time chat, a mailing list, a calendar, an address book, an RSS sink ... sometimes a combination of any of the above, and certainly any other uses which could be added in the future. Furthermore, you can replicate rooms between multiple Citadel nodes, allowing you to set up a federated, distributed messaging environment.