Microsoft had MSN Messenger, there was ICQ and many others, and there was "always" IRC etc., and frankly things were great with gAIM, Pidgin and other messenger aggregators until Google Talk switched off access for third-party apps and launched Hangouts...
I remember my whole family was in gtalk and other jabber talkers. The funny thing they were usable on mobile long before android/ios phones. There were JavaME clients that could run on many common phones. I still miss T9.
GTalk was really in a position to be the #1 messenger.
