aGNeS is a solid BBS system from Vestris Inc. aGNeS allows threaded discussions, article searching, archiving, thread expanding and collapsing, etc. It allows to setup as many web boards as desired with totally different layout , using one CGI. The look and feel of your forum can be just whatever you like using template pages. aGNeS is web-administrable. There are tons of features and options.
panFora is a full featured, high performance Web-based collaboration tool for discussion forums and file sharing. Using standard web browsers and a multi-framed/windowed approach, it has a desktop application feel familiar to users of desktop email/newsgroup tools. A traditional single-frame web layout is also available as a user preference. Extensive admin features allow forums to be created, customized, colorized, reconfigured and maintained, completely from the web. Other unique features include hierarchical topic structure, announcements by groups, and full but safe HTML formatting support in message posts. A popular high performance open-source embedded database is built-in; no database installation is required by the user, making panFora installation fast and easy.
RAT is an RTP audio conferencing and streaming application that allows users to particpate in point-to-point and multi-point audio conferences over the Internet. Developing features include multiple sampling rates, mono/stereo, loss concealment, and IPv4/IPv6 support, and both versions feature encryption and run on a range of platforms.
Spin Chat is a completely Java based Chat application, both server and client. It has been originally developed on Linux and runs excellent on it. It features vast customization possibilities, multi-channels, built-in spam control, graphical administration tools, I18N, channel logging, ignoring, emotes, etc.
W-Agora (Web-Agora) is a database-driven communications system which allows you and your visitors to store and display messages, files, and other information on your web site. More than "just another Web BBS/forum software", W-Agora is designed so it can be easily customizable through a Web browser and the use of templates. It can be used as a BBS, guestbook, download area, or publishing system. Several database backends are supported such as MySQL, Postgres, mSQL, Oracle and DBM.