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