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