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