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