BitlBee allows users to talk to people on the major instant messaging and microblogging networks (including MSN, Google Talk, AIM, and Twitter) from within any IRC client by emulating an IRC server. Virtual channels are created with all of the user's contacts in them, who can be talked to in the channel or in a query. Also, one can participate in group chats and chat rooms like they were normal IRC channels.
Pidgin is a GTK2-based instant messenger application. It supports multiple protocols via modules, including AIM, ICQ, Yahoo!, MSN, Jabber, IRC, Napster, Gadu-Gadu and Zephyr. It has many common features found in other clients, as well as many unique features. Pidgin is not endorsed by or affiliated with AOL TimeWarner, Microsoft, or Yahoo.
BSFlite is a minimalistic, line-based AIM client for Unix (including Mac OS X) and Win32. It is designed with simplicity and efficiency in mind and thus utilises as little RAM and CPU time as possible in order to be friendly to multiuser systems. It uses the OSCAR protocol to communicate with the AIM service.
Off-the-Record (OTR) Messaging is a gaim plugin which allows you to have private conversations over the instant messaging system of your choice. It provides encryption, which prevents someone who intercepts your instant messages from reading them; authentication, which ensures that the correspondent is who you think it is; and perfect forward secrecy, which ensures that no previous conversation is compromised if you lose control of your private keys.
JClaim is an instant message client, tools, and development framework. It supports AIM, ICQ, Yahoo!, MSN, Jabber, Google Talk, and SMS. The framework can be used for designing your own tools. The UI includes spell checking and a lot more. A Web interface is included for remote access.
RapidInformer is a notification system that empowers people to stay connected and take control of the information flow. It enables users to control all notifications they will receive from a single Web application in a consistent manner rather than dealing with different capabilities of each enterprise application, and work with enterprise systems by executing commands directly from instant messaging clients (or the Web application).
Claros inTouch is an AJAX Web mail, instant messenger, address book, and note taker application. The main features are drag and drop support, background attachment uploading, built-in Bayesian spam protection that can identify junk mail on the fly, folder support for the POP3 protocol, compatibility with any POP3/IMAP and SMTP server, operating system independence, support for sending HTML email, and full MIME compatibility. It also features a unique AJAX instant messenger that is capable of talking with a Jabber server.
pidgin-osd is an application that uses the xosd library to print various events on the X root window on receiving incoming messages from pidgin. It is based on gaimnosd 0.7 (the last publically available version). It is mostly like the gaimnosd plugin; the only difference is that an implementation for UTF-8 conversion to the current used locale was added.