ICQ
The ICQ client application and service were initially released in November 1996, freely available to download. ICQ was among the first stand-alone instant messenger (IM)—while real-time chat was not in itself new (Internet Relay Chat (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. ICQ became the first widely adopted IM platform.