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