Is there a messenger application that doesn't require cell phone numbers?

pu1. I think a foreign messenger app would work. Telegram or

2017-12-26

OK

pu2. Facebook messenger is available

2017-12-26

OK

pu3. @2 Facebook Messenger may not need a phone number, but doesn't Facebook itself tell you to include your phone number?

2017-12-26

OK

pu4. Do you put your phone number in LINE, too? When I downloaded it before, I just put in my email without my cell phone number

2017-12-26

OK

pu5. Nate-on is possible

2017-12-26

OK