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