Mastodon already has a few algorithms:

the Home feed is:
- Show me posts for which I follow:
- the author,
- the booster, or
- one of the contained hashtags
- Sorted in the order of most recently posted OR boosted

The Explore feed is something like:
- Show me posts that have been boosted X amount in the last Y minutes
- Sorted by how many boosts
(I don't know the specifics, just guessing)

Plus the ones for the local and global live feeds, and hashtags and lists. And "Who to follow"