ICQ would only just be released in late 1996. Yahoo! Messenger (initially known as Yahoo! Pager) was still two years from being released.

The Pastīack in 1996, when I was still running Windows 95® and before I knew about Linux, I was running mIRC, a then-popular IRC client, which is still popular among Windows users today. I know this was the case for me, until I started frequenting IRC again (after a lengthy hiatus) when I started working on revitalizing the PCLinuxOS Magazine. In a lot of ways, IRC was the Internet social network of its time. Even today, it lives deep in the shadows of the various Internet social networking sites. However, due to the popularity of instant messenger programs, like Yahoo! Messenger and MSN Messenger, IRC has became the forgotten frontier for a lot of computer users. It didn't really take off until 1991, during the Gulf War, when updates about the war kept users 'tuned in' to their IRC chat channels. IRC was started in 1988 (10 years before Yahoo! released Yahoo! Pager, the forerunner of Yahoo! Messenger).

Internet Relay Chat, more commonly referred to as IRC, is one of the older chat services on the internet. The Forgotten Chat Frontier by Paul Arnote

Mirc chat commands