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