A typical architecture has point-to-point structured communication.

You want two components to talk? You add a specific API, carefully structured and bespoke to the purpose, for them to talk.

This works reliably… but also can't create surprising, novel, emergent value.

As the system gets larger, you get a combinatorial explosion of precise, brittle, API wires holding it all together.

It gets more and more expensive to change anything fundamental, or to build a new kind of thing because it needs tie-ins with n^2 other things.

Dynamicland and other systems like blackboard systems try a different way.

If you have a single shared reactive database you can use it as a message bus.

Everything talks directly to the database and then gets updated reactively when something it cares about changes.

Instead of pairwise communication you get a hub and spoke structure.

It's messier and sometimes one thing will change that breaks everything… but it also has the potential for emergent upside, for small bits of activity by a motivated user to unlock game-changing new value in the system.