[bontoJR]

Reactive Streams are just interfaces meant to make interconnection and usage of different libraries easier and faster. The document is meant to avoid the well famous "similar library, different names for same concepts". There's nothing more than that.

In the same page you can find a list of compliant implementations like AKKA or RxJava, so you can easily check out one of them and see how they are implementing these concepts under the hood. The general purpose is good, it makes the switch from framework X to Y easier with the declared goal of provide a standard for asynchronous stream processing with non-blocking back pressure, but, as said before, there's nothing more than that.

About the production, well, some of the listed libraries are widely used, so I guess there are a lot of people actually using this concept in production.

Then, if you want to go further, you can search for Duality, that seems an evolution of Reactive Programming and Reactive Streams.