This is an idea for scaling out certain data when transitioning to a highly clustered architecture.
TL;DR Don't just read, mostly subscribe.
Ideally suited for data that is read often, but written rarely; the higher the r:w ratio, the more you gain from this technique.
This tends to happen to certain data when growing up into a cluster, even if you have data that has a 2:1 ratio for a single server (a very small margin in this context, meaning it is read twice for every time it is written), when you scale it up, you often don't get a 4:2 ratio, instead you get 4:1 because the two writes end up being redundant. That is, if you can publish knowledge of the change fast enough that other edges don't make the same change.