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