In the rich text editor:
@shihai
In a comment:
[shihai](https://www.whistlercrest.com/user/shihai)
For Names and Avatars:
In the rich text editor:
%shihai
In a comment:
[](https://www.whistlercrest.com/user/shihai) [shihai](https://www.whistlercrest.com/user/shihai)