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