[jasonlotito]

JSON is popular because:

JSON can be consumed by JavaScript. This makes pushing JSON rules easy. I can create an API once in JSON. Now, someone can create a web app and make API calls with JavaScript.

That's the reason it's popular.

Another, smaller reason, is:

Many languages/libraries/frameworks provide poor XML support. If your hand coding your XML-RPC/SOAP calls, or dealing with your average XML in a way different then you would JSON, I really don't know what to say other than: Why?

All the other reasons: verbosity, confusion over XML, etc. All those are okay, I guess, but aren't good reasons.

If JSON couldn't be parsed by JavaScript, it wouldn't be used.