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