Agora is a Web-based, threaded discussion tool, similar to Usenet newsgroups. Agora remembers each user's preferences, and allows threaded, unread-only browsing. It offers the ability to manage several different groups, with different themes, forums, and administrators for each group. Agora offers a basic Web-based ICQ client, as well as a Web-based notes system.
IMIRC is an AOL Instant Messenger to IRC gateway. It connects to an IRC network as an IRC server, so it requires a local ircd to run. IMIRC creates nicknames for AIM users as they sign on, and converts HTML codes, which are used by AIM for formatting, to IRC's control code equivalents. Please note that you must either have your own working IRC server or you must find someone willing to let you link to theirs.
Ari's Yahoo Client is a compact, easy-to-use, text-based client for Yahoo! Messenger, based on yahoolib as distributed with GTKYahoo. Ari's Yahoo Client supports displaying your buddy list with the status of each person on it, displaying incoming messages from any Yahoo! ID, and sending messages to any Yahoo! ID (whether or not it is on your buddy list).
Babylon Java Chat is a client and server combo that allows groups to chat and draw over any TCP/IP connection. The client can be run either as a standalone Java application or as an applet launched from a WWW document. It features public and private chatting and drawing, email, file transfers, chat rooms, instant and answering-machine style messaging, and console paging. The drawing canvas enables users to draw freehand, or to create lines, rectangles, ovals, or fonted text, or to paste images from files.
bbs100 is a BBS in the style of DOC and/or YAWC. DOC is a style that remotely resembles Citadel. What's special about bbs100, is that it's a single process daemon that handles all connections at once, while consuming very low cpu resources ( < 1%). It can handle over a thousand simultaneous users. It is highly customizable, is easy to setup, and has many configurable features. bbs100 is almost a must-have for people that want to run a DOC-style BBS.
CGI:IRC is a Perl/CGI program that allows you to use IRC from a Web browser without having to have access to an IRC port. It does not use Java, but it does need a browser capable of rendering frames. It can be used on a Web page to allow users to chat, or it can be used to access chat from behind a firewall.
Citadel is an advanced messaging and collaboration system for groupware and BBS applications. Users can connect to Citadel using any telnet, WWW, or client software. Among the features supported are public and private message bases (rooms), electronic mail, real-time chat, paging, shared calendaring, address books, mailing lists, and more. Unlike other collaboration servers, Citadel provides its own data stores and is therefore extremely easy to install; you don't have to "bring your own" email and database because they're built in. The server is multithreaded and scalable. In addition, SMTP, IMAP, and POP3 servers are built-in for easy connection to Internet mail. Citadel is both robust and mature; it has been in production since 1987.