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