mevove that's not exactly possible with the base Flarum, but:
When a pinned discussion is read on the homepage, it then scrolls down like any other discussion. So once a user has read it, it will no longer appear the top. But pinned discussions always appear at the top when looking at one particular tag.
If the discussion contains a tag that's hidden from the homepage, then the pinned discussion won't appear on the homepage but only under that particular tag.
