JSON is JAVASCRIPT OBJECT NOTATION and is a way to store information in an organized, easy-to-access manner. In a nutshell, it gives us a human-readable collection of data that we can access in a really logical manner. JSON notation is however not only readable by JavaScript, but most languages today have some kind of JSON library for parsing JSON. The importance of JSON is simply due to it’s popularity, it’s no more important than any other way of structuring text.
Each array element holds data specific to that object. Think of a Web Store where you have lots of items for sale. Each item would be stored in one element with all the data like price, description, and even urls to pictures in it. You could then pull that data and use it in your site without hard coding each item to into your HTML template. It is a much-more compact way of transmitting sets of data across network connections as compared to XML. I suggest JSON be used in any AJAX-like applications where XML would otherwise be the “recommended” option. With the rise of AJAX-powered sites, it’s becoming more and more important for sites to be able to load data quickly and asynchronously, or in the background without delaying page rendering. Switching up the contents of a certain element within our layouts without requiring a page refresh adds a “wow” factor to our applications, not to mention the added convenience for our users.