In the rich text editor:
@cosmonstars
In a comment:
[cosmonstars](https://www.worldofgaia.org/user/cosmonstars)
For Names and Avatars:
In the rich text editor:
%cosmonstars
In a comment:
[](https://www.worldofgaia.org/user/cosmonstars) [cosmonstars](https://www.worldofgaia.org/user/cosmonstars)