Windows instant messaging clients

vSide was an Internet-based 3D virtual world that was launched on May 15, 2006. The game is in its public beta phase. However, the game appears to have been discontinued as of May, 2018. Initially developed by American studio Doppelganger, Inc., a studio founded in 2004, the game was acquired in June 2009 by ExitReality, which is the owner and developer. Inside the game's universe, users are called vSiders and can interact with each other through social networking, celebrity entertainment, virtual boutique shopping and self-expression. Membership is free.

Skype is a proprietary telecommunications application operated by Skype Technologies, a division of Microsoft, best known for IP-based videotelephony, videoconferencing and voice calls. It also has instant messaging, file transfer, debit-based calls to landline and mobile telephones (over traditional telephone networks), and other features. It is available on various desktop, mobile, and video game console platforms.

Discord is an instant messaging and VoIP social platform which allows communication through voice calls, video calls, text messaging, and media. Communication can be private or take place in virtual communities called "servers". A server is a collection of persistent chat rooms and voice channels which can be accessed via invite links. Discord runs on Windows, macOS, Android, iOS, iPadOS, Linux, and in web browsers.

MSN Messenger (also known colloquially simply as MSN), 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.

Tencent QQ (Chinese: 腾讯QQ), also known as QQ, is an instant messaging software service and web portal developed by the Mainland Chinese technology company Tencent. QQ offers services that provide online social games, music, shopping, microblogging, movies, and group and voice chat software. As of March 2023, there were 597 million monthly active QQ accounts.

TokBox was a PaaS (Platform as a Service) company that provided hosted infrastructure, APIs and tools required to deliver enterprise-grade WebRTC capabilities. It did so primarily through its proprietary OpenTok video platform for commercial application.

AOL Instant Messenger (AIM, sometimes stylized as 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.

net2phone is a Cloud Communications provider offering cloud based telephony services to businesses worldwide. The company is a subsidiary of IDT Corporation.

Gizmo5 (formerly known as Gizmo Project and SIPphone) was a voice over IP communications network and a proprietary freeware soft phone for that network. On November 12, 2009, Google announced that it had acquired Gizmo5. On March 4, 2011, Google announced that the service would be discontinued as of April 3, 2011.

Wengo was at the beginning of 2004 a subsidiary of French telecom service provider Neuf Cegetel. As of February 2012, Wengo employs 80 people in the Paris headquarters, and is a subsidiary of Vivendi. Wengo is now repositioned as an online personal and consulting services marketplace.