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