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