In the rich text editor:
@b0z0
In a comment:
[b0z0](https://chowlings.com/user/b0z0)
For Names and Avatars:
In the rich text editor:
%b0z0
In a comment:
[](https://chowlings.com/user/b0z0) [b0z0](https://chowlings.com/user/b0z0)