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