Comment by jsnell

You'd still have exactly the same hot write path, it'd just have maybe 50% of the load. That could be a legit optimization, but not having it hardly warrants an incredulous "seriously?" like the OP's.

(And the same for the inverse hybrid strategy of quarantining the writes of highly followed users and handling their fan-out at read time. A neat optimization, and maybe even absolutely once you have accounts with 100M followers. But the vast majority of posts would still be handled via the original strategy.)