After today's IndieWebCamp popup session, I built a way to create unlisted posts on my site that require a secret key in the URL in order to view.
Since all my URLs are more or less sequential, I needed a way to be able to add something to the URL that is unguessable. It was a relatively easy thing to add!
Try viewing this post without the secret string at the end to see the feature in action: https://aaronparecki.com/2021/06/26/9/MXJEJKW
Feedback appreciated, either as replies, GH issues, or at indieweb.org/discuss