facebook has become, dare I say "ubiquitous", it's still the best way to keep in touch with friends regardless of how often you use them, I use my fb maybe once a week, but that one session allows me to catch up with what my friends have been up to. I think messenger apps, including fb messenger, are great when you're young and your social life is limited to only your clique, but I don't see them replacing fb or even becoming a massive threat to fb