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