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