[happosai]

Ah Network effect, That's why we all are still using Skype, microsoft messenger and ICQ.

You don't have to wait for everyone to switch, in fact it's pretty normal to reach different people on different chats.

https://xkcd.com/1810/

[ultratalk]

Well, maybe it was normal ~10 years ago, when that comic was published, but is now getting rarer and rarer, as each new generation consolidates itself on a single platform.