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