Below is a list of defunct instant messaging platforms.
Name, When discontinued - Type of client
AIM (AOL Instant Messenger) 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.
AIM was popular from the late 1990s to the late 2000s in North America, and was the leading instant messaging application in that region. AIM's popularity declined steeply in the early 2010s as Internet social networks like Facebook and Twitter gained popularity, and its fall has often been compared with other once-popular Internet services such as Myspace.In June 2015, AOL was acquired by Verizon Communications. In June 2017, Verizon combined AOL and Yahoo into its subsidiary Verizon Media (Formally Oath Inc). The company discontinued AIM as a service on December 15, 2017.Google Talk
Google Talk (also known as Google Chat) (now Google Hangouts) was an instant messaging service that provided both text and voice communication. The instant messaging service is colloquially known as "Gchat", "Gtalk", or "Gmessage" to its users.Google Talk was also the name of the client applications previously offered by Google to use the service. Google Talk applications were available for Microsoft Windows, Android, BlackBerry, and Chrome OS operating systems. A Google Talk mobile web app had also been previously available. In February 2015, the Windows client was discontinued and ceased to work, with Google recommending users to use Google Hangouts instead. Users of Windows client were instructed to migrate to the Google Hangouts app on the Chrome browser platform. It remained possible to connect to Google Talk with compatible third-party apps such as Pidgin and Gajim.Google dropped support for XMPP federation in May 2014, meaning that it no longer supports communicating with other XMPP servers. However, users can still chat with other non-Google Talk users using third-party XMPP clients such as Adium.