Except MongoDB's and Node.js's incremental improvements in their marketed use case of easy scalability weren't worth your time if you really were concerned with scalability. You would have been better served by existing systems.

So the marketing pivoted to being simple for MongoDB and being SSJS for Node. In Mongo's case scalability was severely hampered by the fundamental design, but many developers fell for the marketing and it cost them. Node.js can perform on some hello world benchmarks, but writing large scalable systems was a minefield of instability, callback hell bugs, lack of JS support for CPU intensive tasks, etc. It's still catching up to systems that existed in 2007.

The incremental improvement on scalability is nowhere to be seen. They do improve some other metric like programmer enthusiasm. Other newcomers did improve on easy scalability after more careful thought and years of effort but the hype machine largely left the topic.

A similar case can be made for HTML5/Flash promises for mobiles. You can use it but it often makes the process more difficult than writing two native apps in many cases. Good luck guessing which.

This is sort of my point about incremental improvement being hard-won, though. It's really difficult to make something that is actually better than other things, even for pretty narrow criteria. That's why I'm always suspicious of things (like the OP) that claim they will bring a major sea-change of betterness across broad criteria.