Just realised that on Mastodon, boosting *is* the algorithm.
There's no code trying to cleverly show me stuff it reckons I'd be into, based on what my contacts are into, instead my contacts are saying "I like this, I bet my contacts would like it too" and that is way smarter than any algorithm.
Thank you, boosters!
@sarajw The most algorithm-y view is the "explore" tab - that's "posts that are getting a lot of boosts, likes, and replies lately on this instance" (i.e., it doesn't matter whether the people interacting are people you follow, just that you share the same instance with them).
Actually I'm not sure if replies are counted, but boosts and likes are.
Sara Joy 
dragonfrog