Skype
Skype is an application which can do :
- voice calls
- video calls
- text chat messaging
with one or multiple persons.
For a full feature list, see http://www.skype.com/en/features/
It is available on multiple platforms (Windows, MacOS X, Linux) and on mobile phones and tablets running iOS (Apple), Android, Windows Phone OS. System Requirements : https://support.skype.com/en/faq/FA10328/what-are-the-system-requirements-for-skype
You can download Skype at https://www.skype.com/ ; You can also use Skype in modern web browsers at https://web.skype.com/
(Screenshot of the Skype for Windows client - Image credit : Microsoft)
Skype is used by ICANN At-Large for its instant messaging features for At-Large (the Community and At-Large Staff) to send and receive chat messages in real-time.
There are group chats in Skype where many At-Large members can chat about At-Large activities and related news.
In late 2014 and through 2015, Skype launched Skype Translator which allows machine translation of text chats and real-time voice interpretation and transcription of several languages. These features are being integrated into the regular Skype desktop clients.