Very early on I was on some small chat service from a regional web provider. Here I learned how to dodge predators and what RP was. I would talk about my small collection of games to random strangers.
I dropped it for a little bit, then started using IRC for a few years. Talking to Runescape friends from another forum, little fan collectives for shows I liked and some metalhead rooms.
With friends I would use MSN messenger or Xfire. Sometimes I would use Ventrillo or Teamspeak for small groups. Skype also popped up here and there.
now I'm on discord.