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