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