When fast is merely not good enough

In the pursuit of applications that are having ever increasing speeds, I am constantly looking around for new ideas and have come across an interesting term, reactive programming that addresses a lot of concepts and puts the possible answer into a single umbrella; or quite simply speaking, gives it a name.
Basically, any web application under this umbrella term is people first - meaning it will inform its client what is happening instead of a delayed page load that can take anywhere between 2 seconds and hours. It always provides a real-time response to the client and responds to clients, events, load and failure.

This is typically done by making the application use following characteristics:

1. Responsive
2. Scalable
3. Resilient
4. Event-Driven

When these applications are cohesively applied, the common pattern/word that emerges gets labelled under the term reactive programming, which is promised by the http://www.reactivemanifesto.org/