Have you looked into your Profile settings here in the (ISC)2 Community?
One page allows you to share your screen names on several instant messenger (IM) systems.
Did the designers of this page stop paying attention to IM system options ten years ago?
Here are the choices:
AIM screen name
MSN Messenger screen name
[There is no option to list "Other" systems with user-defined system names.]
Let's examine that list.
ICQ was originally developed in Israel by MIrabilis. However, several years ago it was bought by Mail.Ru, the largest internet provider and social media company in Russia. An interesting news artile about Mail.Ru is Mail.ru launches in America as My.com, CEO admits Russian government could grab user data.
AIM was shut down in 2018.
After Micro$oft bought Skype, they merged it with MSN Messenger. All old MSN IDs are now Skype IDs.
Yahoo! killed their messenger in July, 2018. See their help page:
Yahoo Messenger will be discontinued
While not obvious, Micro$oft actually has two instantiations of Skype. One is the free public version, and the other is the enterprise version used by organizations that license full M$ Office for internal use. Many enterprise users have two Skype IDs, one for work and one for personal use. (I did when I was employed)
Are any missing?
So, what about Google Hangouts, Facetime, Twitter, FaceBook Messenger (ptui!), WhatSApp, Instagram, Signal, Slack, QQ, and many other modern, still in operation personal communication systems?