In the rich text editor:
@maetoon
In a comment:
[maetoon](https://chowlings.com/user/maetoon)
For Names and Avatars:
In the rich text editor:
%maetoon
In a comment:
[![maetoon's Avatar](https://chowlings.com/images/avatars/default.jpg)](https://chowlings.com/user/maetoon) [maetoon](https://chowlings.com/user/maetoon)