ICQ (I Seek You) is an instant messaging service that was popular in the late 1990s and early 2000s. It was created by an Israeli company called Mirabilis, and was one of the first instant messaging programs to gain widespread use.
ICQ allowed users to send text messages, share files, and chat in real-time with other ICQ users. It also had a feature that allowed users to find and connect with people they knew, based on their email addresses or other personal information.
Although ICQ was very popular in its heyday, it eventually lost ground to newer messaging services like AIM, MSN Messenger, and eventually Facebook Messenger and WhatsApp. However, ICQ is still available today, and continues to be used by some people, particularly in countries where other messaging services are not as popular.