You’re confusing something. Hashtags matter because there is neither a global nor an instance-level full-text search on many platforms (especially Mastodon), only one for your own “storage” (timeline, favs, bookmarks, boosts). Lemmy and kbin have an instance-level full-text search, though.
As long as one person follows the author or discovered a post, it becomes visible via its hashtags to everyone on the same server. That’s why you receive a warning if you write an unlisted post with hashtags, since they wouldn’t work.
What you refer to as algorithm would be applied afterwards. It would collect, sort, filter, or transform those discovered posts according to settings or a generated profile (another algorithm).
You’re confusing something. Hashtags matter because there is neither a global nor an instance-level full-text search on many platforms (especially Mastodon), only one for your own “storage” (timeline, favs, bookmarks, boosts). Lemmy and kbin have an instance-level full-text search, though.
As long as one person follows the author or discovered a post, it becomes visible via its hashtags to everyone on the same server. That’s why you receive a warning if you write an unlisted post with hashtags, since they wouldn’t work.
What you refer to as algorithm would be applied afterwards. It would collect, sort, filter, or transform those discovered posts according to settings or a generated profile (another algorithm).