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