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