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.

How to register icq without email