Pidgin is a chat program which lets you log in to accounts on multiple chat networks simultaneously. This means that you can be chatting with friends on MSN, talking to a friend on Google Talk, and sitting in a Yahoo chat room all at the same time. Pidgin is compatible with the following chat networks out of the box: AIM, ICQ, Google Talk, Jabber/X... More information

Telegram is a cloud-based synchronized messaging app with a focus on speed and security. It's superfast, simple and free. You can use Telegram on all your devices at the same time - [Android](https://telegram.org/dl/android), [iOS](https://telegram.org/dl/ios), [WP](https://telegram.org/dl/wp), [Firefox](https://marketplace.firefox.com/app/telegram... More information

HipChat is group chat, file sharing, video chat & screen sharing built for teams & business. Collaborate from anywhere with apps on desktop & mobile.

Telegram is a cloud-based synchronized messaging app with a focus on speed and security. It's superfast, simple and free. You can use Telegram on all your devices at the same time - [Android](https://telegram.org/dl/android), [iOS](https://telegram.org/dl/ios), [WP](https://telegram.org/dl/wp), [Firefox](https://marketplace.firefox.com/app/telegram... More information

Microsoft Teams is a messaging app for teams where all conversations, meetings, files, and notes can be accessed by everyone, all in one place. It's a place for collaboration and work to happen in the open. Here's why you should use it: - It's great. - It makes communicating one-on-one and with groups a snap. - Collaboration happens in real time.... More information

Spark is an Open Source, cross-platform IM client optimized for businesses and organizations. It features built-in support for group chat, telephony integration, and strong security. It also offers a great end-user experience with features like in-line spell checking, group chat room bookmarks, and tabbed conversations. Combined with the Openfire ... More information

Mumble is a voice over IP (VOIP) application primarily designed for use by gamers, similar to programs such as TeamSpeak and Ventrilo. Mumble uses a client–server architecture which allows users to talk to each other via the same server. It has a very simple administrative interface and features high sound quality and low latency. All communicatio... More information

WhatsApp Messenger is available for iPhone, BlackBerry, Android, Windows Phone and Nokia and yes, those phones can all message each other! Because WhatsApp Messenger uses the same internet data plan that you use for email and web browsing, there is no cost to message and stay in touch with your friends. In addition to basic messaging WhatsApp users... More information

HexChat is a fork of XChat which is free for Linux and Windows. It was originally named XChat-WDK and was created as an alternative to the Shareware version of XChat for Windows, but changed its name because it went far beyond being a simple Windows only version of XChat and efforts to merge into XChat officially hit a dead-end

All-in-one voice and text chat for gamers that’s free, secure, and works on both your desktop and phone.

Miranda IM is a multi-protocol instant messaging client for Windows. Very light on system resources and extremely fast, Miranda IM requires no installation and can be made to fit on a single floppy disk or USB drive. Featuring a powerful plugin-based framework and boasting over 350 plugins, Miranda IM is one of the most flexible and customisable me... More information

Trillian is a proprietary multiprotocol instant messaging application. It can connect to multiple IM services, such as AIM, ICQ, Windows Live Messenger, Yahoo! Messenger, IRC, Novell GroupWise Messenger, Bonjour, XMPP, and Skype networks; as well as social networking sites, such as Facebook, Twitter and MySpace; and email services, such as POP3, I... More information

Jitsi (formerly SIP Communicator) is a free and open source multiplatform voice (VoIP), videoconferencing and instant messaging application for Windows, Linux and Mac OS X. It supports several popular instant messaging and telephony protocols, including open recognised encryption protocols for chat (OTR) and voice/video/streaming and voice/video co... More information

Telegram is a cloud-based synchronized messaging app with a focus on speed and security. It's superfast, simple and free. You can use Telegram on all your devices at the same time - [Android](https://telegram.org/dl/android), [iOS](https://telegram.org/dl/ios), [WP](https://telegram.org/dl/wp), [Firefox](https://marketplace.firefox.com/app/telegram... More information

mIRC is a full featured Internet Relay Chat client for Windows that can be used to communicate, share, play or work with others on IRC networks around the world, either in multi-user group conferences or in one-to-one private discussions. It has a clean, practical interface that is highly configurable and supports features such as buddy lists, fil... More information

Purple Facebook implements the Facebook Messenger protocol into pidgin, finch, and libpurple. While the primary implementation is for purple3, this plugin is back-ported for purple2. The purple-facebook plugin is a replacement for the builtin Facebook XMPP plugin. Facebook is in the process of shutting down their XMPP service, which will... More information

qTox is a powerful [Tox](https://tox.chat/) client that follows the Tox design guidelines while running on all major platforms. ## Features * One to one chat with friends * Group chats * File transfers, with previewing of images * Audio calls, including group calls * Video calls * Tox DNS and Tox URI support * Translations in 26 languages * Avata... More information

Rocket.Chat is an incredible product because we have an incredible developer community. Over 200 contributors have made our platform a dynamic and innovative toolkit, from group messages and video calls to helpdesk killer features. Our contributors are the reason we're the best cross-platform open source chat solution available today.

THE NEW WAY TO ORGANIZE YOUR SERVICES Rambox gives you the possibility to add common services many times you need, all in one place. It's perfect for people who work with many services for business and private accounts.

Gitter is a chat and networking platform that helps to manage, grow and connect communities through messaging, content and discovery. * Free without limits - Enjoy free public communities with unlimited people, message history and integrations. * Simple to create - Simply create your community and start talking - no need to set up any invitation ... More information

RetroShare is an open source, cross-platform, secure, friend-2-friend decentralised communication platform. It lets you to securely chat and share files with your friends, family and coworkers, using a web-of-trust to authenticate peers and OpenSSL to encrypt all communication. RetroShare provides filesharing, chat, messages, forums and channels... More information

Psi is a free instant messaging application designed for the open protocol XMPP network. Fast and lightweight, Psi is fully open-source and compatible with Windows, Linux, and Mac OS X. Extensible Messaging and Presence Protocol (XMPP) is an open technology for real-time communication, which powers a wide range of applications including instant me... More information

WTW is a multi-protocol instant messaging client for Windows. By default this program is Polish-only. English language is here: http://forum.wtw.im/inne-dodatki/angielskie-tlumaczenie-dla-wtw/ ( http://bit.ly/1zRaIJB - direct link). You must place unzipped "en" folder in %USERPROFILE%\AppData\Local\K2T.eu\WTW\Components\I18N, next to "pl" folder. N... More information

Psi is a free instant messaging application designed for the open protocol XMPP network. Fast and lightweight, Psi is fully open-source and compatible with Windows, Linux, and Mac OS X. Extensible Messaging and Presence Protocol (XMPP) is an open technology for real-time communication, which powers a wide range of applications including instant me... More information

From the website: With Instantbird, we intend to redefine the way instant messaging is used, so that it works the way you want. Both simple and powerful, it will help you manage all your real time communications. **Please Note**: This is an automatically updated package. If you find it is out of date by more than a day or two, please contact th... More information

Miranda NG is a successor of a popular multi-protocol instant messaging client for Windows - Miranda IM. Very light on system resources and extremely fast.

Ekiga (formely known as GnomeMeeting) is an open source SoftPhone, Video Conferencing and Instant Messenger application over the Internet. It supports HD sound quality and video up to DVD size and quality. It is interoperable with many other standard compliant softwares, hardwares and service providers as it uses both the major telephony standard... More information

QIP 2012 (IM) — это бесплатное приложение для общения в интернете. Программа предоставляет возможность обмениваться мгновенными сообщениями, совершать видео и аудио звонки, отправлять sms. QIP 2012 (IM) - is a free application to communicate on the Internet. The program provides an opportunity to exchange instant messages, make video and audio ... More information

Voice Communication for Gaming Communities