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