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