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