AIM was an instant messaging and presence computer program created by AOL, which used the proprietary OSCAR instant messaging protocol and the TOC protocol to allow registered users to communicate in real time.
ICQ was a cross-platform instant messaging (IM) and VoIP client founded in June 1996 by Yair Goldfinger, Sefi Vigiser, Amnon Amir, Arik Vardi, and Arik's father, Yossi Vardi. The name ICQ derives from the English phrase "I Seek You". Originally developed by the Israeli company Mirabilis in 1996, the client was bought by AOL in 1998, and then by Mail.Ru Group in 2010.
Instant messaging (IM) technology is a type of synchronous computer-mediated communication involving the immediate (real-time) transmission of messages between two or more parties over the Internet or another computer network. Originally involving simple text message exchanges, modern IM applications and services tend to also feature the exchange of multimedia, emojis, file transfer, VoIP, and video chat capabilities.
Trillian is a proprietary multiprotocol instant messaging application created by Cerulean Studios. It is currently available for Microsoft Windows, macOS, Linux, Android, iOS, BlackBerry OS, and the Web. It can connect to multiple IM services, such as AIM, Bonjour, Facebook Messenger, Google Talk (Hangouts), IRC, XMPP (Jabber), VZ, and Yahoo! Messenger networks; as well as social networking sites, such as Facebook, Foursquare, LinkedIn, and Twitter; and email services, such as POP3 and IMAP.
Messenger was an instant messaging and presence system developed by Microsoft in 1999 for use with its MSN Messenger software. It was used by instant messaging clients including Windows 8, Windows Live Messenger, Microsoft Messenger for Mac, Outlook.com and Xbox Live. Third-party clients also connected to the service. It communicated using the Microsoft Notification Protocol, a proprietary instant messaging protocol. The service allowed anyone with a Microsoft account to sign in and communicate in real time with other people who were signed in as well.
Pidgin is a free and open-source multi-platform instant messaging client, based on a library named libpurple that has support for many instant messaging protocols, allowing the user to simultaneously log in to various services from a single application, with a single interface for both popular and obsolete protocols, thus avoiding the hassle of having to deal with new software for each device and protocol.
Kopete was a multi-protocol, free software instant messaging client released as part of the KDE Software Compilation. Although it can run in numerous environments, it was designed for and integrates with the KDE Plasma Workspaces. Kopete was started because ICQ blocked Licq from their network in 2001. According to the original author, Duncan Mac-Vicar Prett, the name comes from the Chilean Spanish word copete, meaning "a drink with your friends". Kopete has been nominated for multiple awards. The designated successor is KDE Telepathy from the KDE RTCC Initiative.
Miranda NG is an open-source multiprotocol instant messaging application, designed for Microsoft Windows. Miranda NG is free software distributed under the GNU GPL-2.0-or-later.
Adium is a free and open-source instant messaging client for macOS that supports multiple IM networks, including XMPP (Jabber), IRC and more. In the past, it has also supported AIM, ICQ, Windows Live Messenger and Yahoo! Messenger. Adium is written using macOS's Cocoa API, and it is released under the GNU GPL-2.0-or-later and many other licenses for components that are distributed with Adium.
Tlen.pl was an adware licensed Polish instant messaging service. It was fully compatible with the main Polish Gadu-Gadu instant messenger. It was launched in 2001 and discontinued in May 2016.
BitlBee is a cross-platform IRC instant messaging gateway, licensed under the terms of the GNU General Public License.
Skype for Business Server is real-time communications server software that provides the infrastructure for enterprise instant messaging, presence, VoIP, ad hoc and structured conferences and PSTN connectivity through a third-party gateway or SIP trunk. These features are available within an organization, between organizations and with external users on the public internet or standard phones.
Skype for Business is an enterprise software application for instant messaging and videotelephony developed by Microsoft as part of the Microsoft 365 suite. It is designed for use with the on-premises Skype for Business Server software, and a software as a service version offered as part of 365. It supports text, audio, and video chat, and integrates with Microsoft 365 components such as Exchange and SharePoint.
Jingle is an extension to XMPP which adds peer-to-peer (P2P) session control (signaling) for multimedia interactions such as in Voice over IP (VoIP) or videoconferencing communications. It was designed by Google and the XMPP Standards Foundation. The multimedia streams are delivered using the Real-time Transport Protocol (RTP). If needed, NAT traversal is assisted using Interactive Connectivity Establishment (ICE).
Telepathy is a software framework which can be used to make software for interpersonal communications such as instant messaging, Voice over IP or videoconferencing. Telepathy enables the creation of communications applications using components via the D-Bus inter-process communication mechanism. Through this it aims to simplify development of communications applications and promote code reuse within the free software and open source communities by defining a logical boundary between the applications and underlying network protocols.
Empathy was an instant messaging (IM) and voice over IP (VoIP) client which supported text, voice, video, file transfers, and inter-application communication over various IM communication protocols.
K Desktop Environment 3 is the third series of releases of the K Desktop Environment. It was one of the two major desktop environments for GNU/Linux systems between 2002 and 2008. There are six major releases in this series. After the release of KDE 4, version 3.5 was forked into the Trinity Desktop Environment.
MSN Messenger, later rebranded as Windows Live Messenger, was a cross-platform instant-messaging client developed by Microsoft. It connected to the now-discontinued Microsoft Messenger service and, in later versions, was compatible with Yahoo! Messenger and Facebook Messenger. The service was discontinued in 2013 and was replaced by Skype.
Jami is a SIP-compatible distributed peer-to-peer softphone and SIP-based instant messenger for Linux, Microsoft Windows, macOS, iOS, and Android. Jami was developed and maintained by the Canadian company Savoir-faire Linux, and with the help of a global community of users and contributors, Jami positions itself as a potential free Skype replacement.
Instantbird is a discontinued cross-platform instant messaging client based on Mozilla's XULRunner and the open-source library libpurple used in Pidgin. Instantbird is free software available under the GNU General Public License. Over 250 add-ons allow user customization of, and addition of, features. On October 18, 2017, Florian Quèze announced that "... we are stopping development of Instantbird as a standalone product."
