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