[tasogare]

Not really, WhatsApp is used in Europe, Middle East and India. Japan, Taiwan, Thailand, South Korea are on Line. China Weibo I think. Even in the West the market is fragmented with Signal, Telegram, Facebook Messenger, Instagram, Discord, etc.

[lxgr]

The important commonality here being “not on iMessage”.

[WanderPanda]

„just“ Europe, Middle East, India and South America (btw)