Ceilidh
Ceilidh is a platform-independent engine for collaboration and document sharing on the Web. It allows users to write text/html web messages that are automatically converted into hypertext and that appear as individual components of a threaded list of messages. Ceilidh also offers the ability to attach files to messages as well as user-selectable e-mail notification of new messages. It can also be used to post bulletins on the Web and even to function as a web-based e-mail listserver.