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|Initial release||November 1996|
|Stable release||8.0.6008 / 22 March 2013|
|Operating system||Windows, Linux, Mac OS X, Web, mobile phones|
|Type||Instant messaging client|
The first version of the program was released in November 1996 and ICQ became the first Internet-wide instant messaging service, later patenting the technology. AOL acquired Mirabilis on June 8, 1998, for US$287 million in cash up front and $120 million in additional payments over three years.
Mirabilis was first established in June 1996 by five Israelis: Yair Goldfinger, Sefi Vigiser, Amnon Amir, Arik Vardi, and Arik's father Yossi Vardi. They recognized that many people were online accessing the Internet through a non-UNIX operating system, and that there was no software that enabled an immediate connection between them.
The technology Mirabilis developed for ICQ was distributed free of charge. The technology's success encouraged AOL to acquire Mirabilis on June 8, 1998, for US$287 million up front and $120 million in additional payments over three years. At the time, this was the highest price ever paid to purchase an Israeli technology company.
ICQ's management changed at the end of 2003. Under the leadership of the new CEO, Orey Gilliam, who also assumed the responsibility for all of AOL's messaging business in 2007, ICQ resumed its growth and turned into a highly profitable company, and one of AOL's most successful businesses.
ICQ was also used by Adarbad Master and Keyur Patel to build AT&T's first web platform in USA.
Eliav Moshe replaced Gilliam in 2009 and became ICQ's managing director.
- ICQ features include offline user messaging, multi-user chats, free daily-limited SMS sending, resumable file transfers, greeting cards, multiplayer games and a searchable user directory. Users can use emoticons while chatting with other users.
- ICQ6 was launched on April 17, 2007, and offered a single communication platform that combines the various user options: instant messaging services, free SMS from ICQ to mobile, voice and video communication. The software's new sound gallery was orchestrated by the Israeli psychedelic trance duo Infected Mushroom. Among the new additional features in ICQ6 are Quick IM, which allows users to send a short message without opening a conversation window, a "follow me" service directly to the user’s mobile, a multi-chat service and support for Zlango, the animated icons language.
Additional products 
ICQ provides all users additional services and content products:
- ICQ TV—An online video magazine. The magazine broadcasts content for teens 24/7.
- ICQ SIM Card (together with United Mobile)—A SIM card that enables users traveling across Europe to use their cellular telephone while paying a discount price.
- ICQ Game Center—By clicking a button in the contact list, the game center is available for users. A games platform that enables the user to play with and/or against other users.
- ICQ2Go—A web instant messaging option for users who cannot download the program onto their computer (for various reasons, like firewall for instance). ICQ2Go uses a ‘port-80’ browser for this type of communication feature.
- ICQ for Mac (Beta)—Released in February 2010, a version of the client that was developed using the Adobe AIR platform, making it usable on additional operating systems which support the AIR runtime, such as Linux.
Also, users can choose and select their own avatar for their profile page. In this way, they can protect their privacy.
ICQ users are identified by numbers called UIN, distributed in sequential order. The UIN was first invented by Mirabilis, as the user name assigned to each user upon registration. The meaning is either Universal Internet Number or Unified Identification Number. Issued UINs started at number 10000 (5 digits) and every user receives a UIN when first registering to ICQ. As of ICQ6, users are also able to log in using the specific e-mail address they associated with their UIN during the registration process. Unlike other instant messaging software or web applications, on ICQ the only permanent user info is the UIN, although it is possible to search for other users using their associated e-mail address or any other detail they have made public (by updating it in the public profile). In addition, the user can change all of his or her personal information, including screen name and e-mail address, without having to re-register. Since 2000, ICQ and AIM users are able to add each other to their contact list without the need for any external clients. As a response to UIN theft or sale of attractive UINs, ICQ started to store email addresses previously associated to a UIN. As such, UINs that are stolen can sometimes be reclaimed. This applies only if (since 1999 and onwards) a valid primary email address was entered into the user profile.
Development history 
First versions 
ICQ was developed in 1996 by Mirabilis. The company was founded by four young Israelis: Yair Goldfinger, Arik Vardi, Sefi Vigiser and Amnon Amir. After AOL bought it, it was managed by Ariel Yarnitsky and Avi Shechter.
America Online acquired Mirabilis on June 8, 1998, for $407 million ($287 million in cash and $120 million over a three-year period based on growth performance levels).
Later versions 
- ICQ 99a/b a very early and much loved client that introduced many people to the world of instant messenging
- ICQ 2000 incorporated into Notes and Reminder features.
- ICQ 2001 included server-side storage of the contact list, allowing for its synchronization on multiple computers.
- On December 19, 2002, AOL Time Warner announced that ICQ had been issued a United States patent for instant messaging.
- ICQ 2002 was the last completely advertising-free ICQ version.
- ICQ Pro 2003b was the first ICQ version to use the ICQ protocol version 10. However, ICQ 5 and 5.1 use version 9 of the protocol. ICQ 2002 and 2003a used version 8 of the ICQ protocol. Earlier versions (ICQ 2001b and all ICQ clients before it) used ICQ protocol version 7.
- ICQ 4 and later ICQ 5 (released on Monday, February 7, 2005), were upgrades on ICQ Lite. One addition was Xtraz, which offers games and features intended to appeal to younger users of the Internet. ICQ Lite was originally an idea to offer the lighter users of instant messaging an alternative client which was a smaller download and less resource-hungry for relatively slow computers.
- ICQ 5 introduced skins support. There are few official skins available for the current ICQ 5.1 at the official website; however, a number of user-generated skins have been made available for download.
- ICQ 6, released on April 17, 2007, was the first major update since ICQ 4. The user interface has been redesigned using Boxely, the same rendering engine used in AIM Triton. This change adds new features such as the ability to send IMs directly from the client's contact list. ICQ has recently started forcing users of v5.1 to upgrade to version 6. Those who do not upgrade will find their older version of ICQ does not start up. Although the upgrade to version 6 should be seen as a positive thing, some users may find that useful features such as sending multiple files at one time is no longer supported in the new version. At the beginning of July 2008, a network upgrade forced users to stop using ICQ 5.1 - applications that identified themselves as ICQ 5, such as Pidgin, were forced to identify themselves as ICQ 6. There seems to be no alternative for users other than using a different IM program or patching ICQ 5.1 with a special application.
- ICQ 7.0, released on January 18, 2010. This update includes integration with Facebook and other websites. It also allows custom personal status similar to Windows Live Messenger (MSN Messenger). ICQ 7.0 does not support traditional Chinese on standard installation or with the addition of an official language pack. This has made its adoption difficult with the established user base from Hong Kong and Taiwan where traditional Chinese is the official language.
- ICQ 8, released on February 5th, 2012 - "Meet the new generation of ICQ, Enjoy free video calls, messages and SMS, social networks support and more."
According to security analyst Jeffrey Carr, use of ICQ may cause security problems because it was purchased by Russian investment company Digital Sky Technologies. ICQ has fallen out of fashion in US and Britain, but it remains popular in Eastern Europe and Russia. Carr says the new ownership may be used by Russia's powerful secret service, the FSB (formerly the KGB) since Russian law, like the American law, requires ICQ to open its logs whenever they want". But so are other IMs too (see Skype security, YIM SPIM, AIM vulnerabilities etc.).
Privacy and copyright 
When accepting "ICQ Terms Of Service — Acceptable Use Policy" (2000), a user gives all the copyright in the posted information to ICQ Inc. This implies that ICQ Inc. may publish, distribute etc. any messages sent through the system that could be meant to be private:
"You agree that by posting any material or information anywhere on the ICQ Services and Information you surrender your copyright and any other proprietary right in the posted material or information. You further agree that ICQ Inc. is entitled to use at its own discretion any of the posted material or information in any manner it deems fit, including, but not limited to, publishing the material or distributing it."
ICQ accounts may be deleted by user .
Pressure on alternative clients 
AOL pursued an aggressive policy regarding alternative ("unauthorized") ICQ clients.
- In July 2008 changes were implemented on ICQ servers causing many unofficial clients to stop working. These users received an official notification from "ICQ System".
- On December 9, 2008, another change to the ICQ servers was made. The clients that were sending Client IDs not matching ICQ 5.1 or higher stopped working.
- On December 29, 2008, ICQ press service distributed a statement characterizing alternative clients as dangerous.
- On January 21, 2009, ICQ servers started blocking all unofficial clients in Russia and Commonwealth of Independent States countries. Users in Russia and Ukraine received a message from UIN 1:
- ICQ не поддерживает используемую вами версию. Скачайте бесплатную авторизованную версию ICQ с официального web-сайта ICQ.
- The version you are using is not supported by ICQ. Download a free authorized ICQ version from ICQ’s official website."
On icq.com there is an "important message" for Russian-speaking ICQ users: "ICQ осуществляет поддержку только авторизированных версий программ: ICQ Lite и ICQ 6.5." ("ICQ supports only authorized versions of programs: ICQ Lite and ICQ 6.5.")
- On February 3, 2009, the events of January 21 have repeated.
AOL's OSCAR network protocol used by ICQ is proprietary and using a third party client is a violation of ICQ Terms of Service, nevertheless a number of third-party clients have been created by using reverse-engineering and protocol descriptions. These clients include:
- Adium: supports ICQ, Yahoo!, AIM, MSN, Google Talk, XMPP, and others, for Mac OS X
- Ayttm: supports ICQ, Yahoo!, AIM, MSN, IRC, and XMPP
- bitlbee: IRC gateway, supports ICQ, Yahoo!, AIM, MSN, Google Talk, and XMPP
- centericq: supports ICQ, Yahoo!, AIM, MSN, IRC and XMPP, text-based
- climm (formerly mICQ): text-based
- Easy message: supports MSN, AIM, ICQ, and Yahoo!
- eBuddy: web-based, supports MSN, AIM, Yahoo!, ICQ, Google Talk and MySpace Chat
- Fire: supports ICQ, Yahoo!, AIM, MSN, IRC, and XMPP, for Mac OS X
- Jimm: supports ICQ, for Java ME mobile devices
- Kopete: supports AIM, ICQ, MSN, Yahoo, XMPP, Google Talk, IRC, Gadu-Gadu, Novell GroupWise Messenger and others, for Unix-like
- Mandarin IM: supports ICQ, XMPP and Mail.Ru Messaging Protocol, for Java ME mobile devices
- Meebo: AJAX-based, supports ICQ, AIM, Yahoo!, MSN, Google Talk and XMPP
- Meetro: IM and social networking combined with location; supports AIM, ICQ, MSN, Yahoo!
- Miranda IM: supports ICQ, Yahoo!, AIM, MSN, IRC, Google Talk, XMPP, Gadu-Gadu, BNet and others, for Windows
- Naim: ncurses-based
- Palringo: Supports various protocols such as AIM, Yahoo!, MSN, XMPP, Google Talk, Gadu-Gadu, ICQ, Facebook IM, as well as its own proprietary IM protocol under the same name
- Pidgin (formerly Gaim): supports ICQ, Yahoo!, AIM, Gtalk, MSN, IRC, XMPP, Gadu-Gadu, SILC, Meanwhile (IBM Lotus Sametime) and others
- PlayXpert: supports ICQ, AOL Instant Messenger, Google Talk, Sony Station Friends, MSN, Yahoo! Messenger, and Xfire
- QIP: supports ICQ, AIM, and partially XMPP and XIMSS
- stICQ: supports ICQ, for Symbian OS
- Trillian: supports ICQ, Yahoo!, AIM, MSN, IRC, Google Talk, XMPP and others
AOL supported clients include:
See also 
- Comparison of instant messaging clients
- Comparison of instant messaging protocols
- LAN messenger
- Online chat
- Windows Live Messenger
- "BBC NEWS | Technology | AOL wins instant messaging case". news.bbc.co.uk. December 19, 2002. Retrieved 2010-03-31.
- "America Online to Buy Internet Chat Service for $287 Million". New York Times. June 9, 1998.
- ICQ Surpasses 100 Million Registered Users, Time Warner Press Release - May 09, 2001
- "AOL sells ICQ to Russian internet company". Financial Times. April 28, 2010.
- "Russian spooks could claim web chat for themselves". Retrieved 2010-07-15.
- "End ICQ Spam". Retrieved 2010-03-09.
- "ICQ Terms Of Service — Acceptable Use Policy"
- Официальное заявление ICQ: использовать QIP — опасно (in Russian)
- AOL Engaged in Dubious Competition Practices for ICQ in Russia
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