Tetra-WebBBS is a web-based message board system. Unlike most other such boards, Tetra-WebBBS lets users define how they display the message index and the messages. They can tailor the index based on date and/or subject. They can view the index as threaded or unthreaded (flat) lists. They can view the messages in single message or guestbook style. A wide variety of options are available to both the administrator and the users.