[MYEUHD]

Whatsapp, Zoom and Kik Messenger use XMPP under the hood.

Just because it's not well-known doesn't mean it's not widely used

[betaby]

Whatsapp used XMPP many years ago, not today though.

[alexchantavy]

I miss when Facebook Messenger let you connect to it with XMPP back in the day so you could have it together with your other msging services on Adium/Pidgin