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