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