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