In the rich text editor:
@2000s
In a comment:
[2000s](https://chowlings.com/user/2000s)
For Names and Avatars:
In the rich text editor:
%2000s
In a comment:
[![2000s's Avatar](https://chowlings.com/images/avatars/default.jpg)](https://chowlings.com/user/2000s) [2000s](https://chowlings.com/user/2000s)