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