In the rich text editor:
@brightberries
In a comment:
[brightberries](https://www.worldofgaia.org/user/brightberries)
For Names and Avatars:
In the rich text editor:
%brightberries
In a comment:
[](https://www.worldofgaia.org/user/brightberries) [brightberries](https://www.worldofgaia.org/user/brightberries)