As a response to UIN theft or sale of attractive UINs, ICQ started to store email addresses previously associated with a UIN. Since 2000 ICQ and AIM users are able to add each other to their contact list without the need for any external clients. 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. 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 their account's public profile. As of ICQ6 users are also able to log in using the specific e-mail address they associated with their UIN during the initial registration process. Issued UINs started at '10,000' (5 digits) and every user receives a UIN when first registering with ICQ. The UIN was invented by Mirabilis, as the user name assigned to each user upon registration. ICQ users are identified and distinguished from one another by UIN, or User Identification Numbers, distributed in sequential order. Since 2013, ICQ has 11 million monthly users. At the time of the Mail.Ru acquisition in 2010, there were around 42 million daily users.
Whilst Internet Relay Chat programs, like Pirch and mIRC, dominated the market for many years, their popularity began to fall in the face of mobile computing which had begun to take hold with PalmPilot and the fledgling Microsoft Windows Compact Edition.Īt its peak around 2001, ICQ had more than 100 million accounts registered. ICQ was among the first stand-alone instant messenger and the first online instant messenger service - while real-time chat was not in itself new to the internet (IRC being the most common platform at the time), the concept of a fully centralized service with individual user accounts focused on one-on-one conversations set the blueprint for later instant messaging services like AIM, and its influence is seen in modern social media applications. Users could register an account and would be assigned a number, like a phone number, for others to be able to contact them (users could also provide handles).
The ICQ client application and service were initially released in November 1996 and the client was freely available to download.
Ownership of ICQ passed from Mirabilis to AOL in 1998, and from AOL to Mail.Ru Group in 2010. The name ICQ derives from the English phrase "I Seek You". ICQ is an instant messaging client that was first developed and popularized by the Israeli company Mirabilis in 1996.