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