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