Google Talk

Google Talk is an instant messaging service that provides both text and voice communication. The instant messaging service is colloquially known as "gchat" to its users, although Google does not endorse this name.

Google Talk is also the name of the client applications offered by Google to access the service. Google Talk applications are available for Microsoft Windows (XP, Server 2003, Vista, and Windows 7), Android, Blackberry, and Google Chrome OS operating systems.

Because the Google Talk servers communicate with clients using an open protocol, XMPP, the service can also be accessed using any other client that supports XMPP. Such clients are available for a number of operating systems not supported by the Google Talk client.

VoIP in Google Talk uses an older version of what became the Jingle protocol. The technology used within the Google server network, however, is not publicly known.

Interoperability
Google has announced that a major goal of the Google Talk service is interoperability. Google Talk uses XMPP to provide real-time extensible messaging and presence events, including offline messaging and voice mailing. Google Talk supports messaging with any service provider that supports the XMPP protocol. This includes Earthlink, Gizmo Project, Tiscali, Netease, Chikka, MediaRing, and, according to Google, "thousands of other ISPs, universities, corporations and individual users."

Other XMPP clients such as Pidgin and Psi are compatible with Google Talk's text chat (IM), allowing text chat with XMPP users on a variety of platforms.

Product integration
Google Talk is integrated into Gmail. Users can send instant messages to other Gmail users. As it works within a browser, the Google Talk client does not need to be downloaded to send instant messages to Gmail users.

Conversation logs are automatically saved to a Chats area in the user's Gmail account. This allows users to search their chat logs and have them centrally stored in their Gmail accounts. For a long time it wasn't possible to directly download chat logs that are not attached to an e-mail conversation, although some workarounds had been found. However, on September 15, 2011, Google announced a new feature of its Google Takeout program that allows users to download chat logs via IMAP.

Google has also integrated Google Talk with Orkut. This enables Google Talk users to interact with registered Orkut users, by sending and receiving 'scraps' within Orkut.

Google Talk Gadget is a web based module that may be embedded in iGoogle and other web pages, allowing text chat with users of Google Talk.

Google+ is integrated into Google Talk. In the standalone client and the Google Talk widget embedded into Gmail and Google+, Google+ contacts appear in the contacts list; their respective circles are shown in Google+'s iteration of the widget.

Voice and Video
It is possible to place and receive phone calls from within gmail by using Google Talk. In order to receive calls, however, the user must upgrade to a full Google Voice account. Initially, users outside of the US cannot upgrade to a full Google Voice account and cannot receive phone calls in Gmail. Google Voice is now available in several countries and languages.

Google Talk at some point allowed users to leave a voicemail for a contact whether or not they are signed into Google Talk. . This service was, however, discontinued in 2011. Messages can be up to 10 minutes long and are sent to the recipient's email. Messages can be sent with or without first ringing the recipient's phone number.

Google also provides a Voice and Video Chat browser plugin (not to be confused with the standalone Google Talk client) that supports voice and video chat between Gmail users. The plugin is available for Windows (XP, Vista, and 7), Mac OS X (only on Intel-based Macs), and Linux (Debian, Ubuntu, Fedora, and OpenSUSE packages available, but the binaries work on other systems) The plugin must be downloaded and installed, but otherwise seamlessly integrates into the Gmail interface.

Encryption
The connection between the Google Talk client and the Google Talk server is encrypted, except when using Gmail's chat over HTTP, a federated network that doesn't support encryption, or when using a proxy like IMLogic. End-to-end messages are unencrypted. Google plans to add support for chat and call encryption in a future release. Some XMPP clients natively support encryption with Google Talk's servers. It is possible to have end-to-end encryption over the GTalk network using OTR (off-the-record) Encryption.

Offline messaging
On October 31, 2006, Google introduced offline messaging to Google Talk. This allows users to send messages to their contacts, even if they are not signed in. They will receive the messages when they next go online even if the user who has sent it is offline. This only works between gmail-accounts though, and doesn't work between Google Talk servers and other XMPP servers.

Mobile device compatibility
On June 30, 2006, Nokia released new software for their Nokia 5230 Internet Tablet, that included Google Talk as one of the compatible VoIP clients, because of the XMPP-based software. Another Google Talk-compatible device is Sony's mylo, released on September 15, 2006. A Google Talk client is also available for BlackBerry devices from the Blackberry site. Google Talk support is also integrated in Google Android devices, but does not support voice and video calls below Android version 2.3.4. This was released in April 2011 for the Google Nexus S.

However, given that Google Talk provides XMPP protocol, most mobile phones for which a suitable XMPP client exists could also offer Google Talk service, at least theoretically (depending on the handset, the user may encounter security warnings because of unsigned Java ME midlets or limits put in place by the mobile service provider). Mobile clients specially designed for Google Talk exist as well.

Most phones support the IMPS protocol, and there are hybrid XMPP/IMPS networks (through XMPP transports, or specially designed hybrid servers), which can also contact GoogleTalk users. The Google Talk service itself is unusable from IMPS (that means, you cannot log with your Gmail account, but you can talk with your Gmail friends with your IMPS account from your mobile phone).

For most smartphones, including Symbian-based as well as Android, third-party applications such as Nimbuzz and Fring include support for Google Talk accounts, including VoIP calls.

Text formatting
Google Talk does not provide the user with a menu for text formatting. Nevertheless Google talk does support some text formatting features like making text bold and italic. To write message in bold, a user should type the required text between two asterisks (*), for example *this text would be bold in Google Talk*. Similarly for making text italic, one should put text between underscores(_)and for strike-through in text content one should put text in between dashes(-).

Access restrictions
Downloading Google Talk is banned from countries on the United States Office of Foreign Assets Control (OFAC) sanction list, including Cuba, Iran, Libya, North Korea, Sudan and Syria.

History
After the rumor of a Google-branded "communications tool" service had been reported by The New York Times and detailed by the Los Angeles Times on August 22, 2005, the subdomain talk.google.com was found to have an active XMPP server. Two methods of logging into the server were discovered soon after and the ensuing response by eager bloggers revealed to numerous others how to login before the official release by Google.

On the evening of August 23, many logged-in users using port 5222 to connect were disconnected and unable to log back in. Users using port 5223 to connect were still able to log in, and at 04:12:52 UTC those users received a broadcast instant message from gmail.com, an apparently official username used by Google to communicate with their user base, that stated "The broken link has been fixed. Thanks for being our first users!" Port 5222-connectivity was found to have been re-enabled. On August 24, Google Talk was officially launched.

On December 15, 2005, Google released libjingle, 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." Libjingle is a library of the code that Google uses for peer-to-peer communication, and was made available under a BSD license.

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

On February 7, 2006, Gmail added the ability to chat with a built-in XMPP client.

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

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.

In August of that year Google's and eBay's announced that they would look into making Google Talk users able to communicate with Skype: "The companies will also explore interoperability between Skype and Google Talk via open standards to enable text chat and online presence." However with Microsoft's acquisition of Skype on the May 10, 2011 such interoperability might have been suspended between Google and eBay.

Google integrated Google Talk with Orkut on November 8, 2006.

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

A screen shot was posted on May 18, 2007 as part of the Google Apps presentation, showing some phone integration in Google Talk. A Google engineer confirmed they have been using it internally for some time on March 2, 2008.

On November 26, 2007, Google Talk released Group Chat capabilities. Before this, users could chat with only one person per window. Group chat allows many users to chat with each other in an environment similar to IRC.

On December 6, 2007, Google upgraded its Gmail integrated chat to include AOL Instant Messenger chat capability. This allows Gmail users to sign into the AIM chat service and communicate with any AIM user while still being signed on to the Google Talk service. The Google Talk gadget and client have not been upgraded to enable this feature yet, and no announcement has been made as to when it will be made available.

On February 25, 2008, Google added a feature called chatback, which allows a Google Talk account owner to chat with people who don't have one. The account owner first has to create a badge, which can be included in webpages. This badge shows the current availability of the owner. Clicking on the badge results a chat request notification to the owner who can respond by clicking on the specified URL. During the conversation both parties have to use the Google Talk Gadget and both parties remain anonymous to each other, even the Google Account name of the owner is not revealed to the other peer.

On November 11, 2008, Google Chat (voice and video chat) was launched enabling computer to computer voice and video chat.

Clues from one of the first Google Chrome December 2008 revisions suggests that a new Talk client is in the works.

Google came out with a Voice and Video Chat browser plugin in 2008.

As XMPP Jingle specifications became a Draft Standard, Google updated libjingle to version 0.5.1 and stated that "Google Talk is in the process of being updated to be in full compliance with the Jingle specifications."

Google has a version of Google Talk called Google Talk, Labs edition, though it lacks many features of Google Talk's other releases.