[sewen]

The main point is that this new architecture has many interesting advantages over the standard Rails & database approach.

By logging all the interaction events and computing application state via a stream processor, you get all the benefit's of a log-centric architecture. Building different services as "views" over the history of interactions, forking the stream to test new applications, replaying data to test different recommender models, ramping up models on historic data and falling in with real-time data for continuous updates. That all becomes the same thing.

And for many use cases, you get better performance on less hardware because you have a simpler concurrency model.