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