Google Talk was an instant messaging service that provided both text and voice communication.

[1] The instant messaging service was variously referred to colloquially as Gchat, Gtalk, or Gmessage among its users.

[8][9] Users of Windows client were instructed to migrate to the Google Hangouts app on the Chrome browser platform.

As it worked within a browser, the Google Talk client did not need to be downloaded to send instant messages to Gmail users.

Conversation logs were automatically saved to a "Chats" area in the user's Gmail account.

This allowed users to search their chat logs and have them centrally stored in their Gmail accounts.

For a long time, it was not possible to directly download chat logs that were not attached to an email conversation,[11][12] although some workarounds had been found.

In order to receive calls, however, the user had to upgrade to a full Google Voice account.

[17] Initially, users outside of the US could not upgrade to a full Google Voice account or receive phone calls in Gmail.

Some XMPP clients natively supported encryption with Google Talk's servers.

This was released in April 2011 for the Google Nexus S.[28] However, given that Google Talk provided XMPP protocol, most mobile phones for which a suitable XMPP client existed[29] could also offer Google Talk service, at least theoretically (depending on the handset, the user may have encounter security warnings because of unsigned Java ME MIDlets or limits put in place by the mobile service provider).

On the evening of August 23, many logged-in users using port 5222 to connect were disconnected and unable to log back in.

On December 15, 2005, Google released libjingle,[34] a C++ library to implement Jingle, "a set of extensions to the IETF's Extensible Messaging and Presence Protocol (XMPP) for use in voice over IP (VoIP), video, and other peer-to-peer multimedia sessions.

"[35] Libjingle is a library of the code that Google uses for peer-to-peer communication, and was made available under a BSD license.

[36] In 2006, Google reported that they were working on adding new features such as supporting SIP in a future release, which would broaden the userbase for the program.

[37] On January 17, 2006, Google enabled server-to-server communications, federating itself with any XMPP server that supported the dialback protocol.

[38] On February 7, 2006, Gmail received chat functionality,[39] using Ajax for server–browser communication, and was integrated with Google Talk.

On March 14, 2007, Google released the Google Talk Gadget, an Adobe Flash-based Talk module that could be added to iGoogle (formally the Google Personalized Homepage) or embedded in any web page, thus, allowing chat from any operating system which was supported by Adobe Flash Player as long as Adobe Flash Player was installed.

[21] Clues from one of the first Google Chrome builds in December 2008 suggested that a new Talk client was in the works.

Mr. Singhal stated that as long as Google Talk was available, 3rd party clients could be expected to continue to work.

As of that date, connection attempts returned an error message stating "Username and password do not match."

Those users received a notification e-mail stating, in part: "We noticed you recently tried using the Google Talk app for Windows.