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