In the rich text editor:
@M0N0
In a comment:
[M0N0](https://chowlings.com/user/M0N0)
For Names and Avatars:
In the rich text editor:
%M0N0
In a comment:
[![M0N0's Avatar](https://chowlings.com/images/avatars/default.jpg)](https://chowlings.com/user/M0N0) [M0N0](https://chowlings.com/user/M0N0)