In the rich text editor:
@P0KERUS
In a comment:
[P0KERUS](https://chowlings.com/user/P0KERUS)
For Names and Avatars:
In the rich text editor:
%P0KERUS
In a comment:
[![P0KERUS's Avatar](https://chowlings.com/images/avatars/default.jpg)](https://chowlings.com/user/P0KERUS) [P0KERUS](https://chowlings.com/user/P0KERUS)