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