I remember seeing a talk on this around a year ago, and while it did have some important backing and solve some interesting problems, there wasn't much in terms of examples of people using it in production.
Is this still the case? I guess with it hitting 1.0 it's more likely now, but I'd still be interested to hear if anyone's had much experience with this up until now.
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.
For evidence of people in production now, you will find more users of RxJava which has been providing similar functionality for a while (including backpressure support).
I think this convention is one for the future and this release marks the start of adoption. I think the hope is that more implementations will come in the future and one goal is to allow the simple connection of reactive streams and allow the building complex distributed systems.
I don't think it's meant to be used directly. It's a minimal api (just 4 interfaces) that can be used by various reactive frameworks to interoperate with eachother.
Is this still the case? I guess with it hitting 1.0 it's more likely now, but I'd still be interested to hear if anyone's had much experience with this up until now.