When imperfect systems are good: Bluesky's lossy timelines

I wonder why timelines aren't implemented as a hybrid gather-scatter choosing strategy depending on account popularity (a combination of fan-out to followers and a lazy fetch of popular followed accounts when follower's timeline is served).

When you have a celebrity account, instead of fanning out every message to millions of followers' timelines, it would be cheaper to do nothing when the celebrity posts, and later when serving each follower's timeline, fetch the celebrity's posts and merge them into the timeline. When millions of followers do that, it will be cheap read-only fetch from a hot cache.

This is probably what we'll end up with in the long-run. Things have been fast enough without it (aside from this issue) but there's a lot of low-hanging fruit for Timelines architecture updates. We're spread pretty thin from a engineering-hours standpoint atm so there's a lot of intense prioritization going on.

Just to be clear, you are a Bluesky engineer, right?

off-topic: how has been dealing with the influx of new users after X political/legals problems aftermath? Did you see an increase in toxicity around the network? And how has you (Bluesky moderation) dealing with it.

There's nothing wrong with being partisan if you're partisan against fascists who want to destroy democracy and the rule of law.

Yup. This is a well-tread philosophical problem: the Paradox of Tolerance. Greater minds have concluded "to protect tolerance, one has to be intolerant of intolerance."

And, as always, bsky is a place of business - it is not a public venue. They can decide not to admit individuals who would threaten their business.