In the rich text editor:
@d0rmu
In a comment:
[d0rmu](https://chowlings.com/user/d0rmu)
For Names and Avatars:
In the rich text editor:
%d0rmu
In a comment:
[![d0rmu's Avatar](https://chowlings.com/images/avatars/default.jpg)](https://chowlings.com/user/d0rmu) [d0rmu](https://chowlings.com/user/d0rmu)