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