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