Building on top of what a website is, I wanted to demonsterate how an API really isn't that different from a website. To help illustrate I pulled together some working examples for us to explore.
This is a live demo meant to help understand the evolution from web to API, showing how a website returns HTML for humans, and RSS, XML, JSON, and other machine readable content for other application, systems, computers, and mobile devices.
Click on any of the HTML, RSS, XML, or JSON links below, and it will call the page, and load in text area below.
You can view the actual site that runs this at http://website.apievangelist.com. It is not meant to be a complete website or API, just showing how the same URL, can return content, data, and other resources for use in many different scenarios.
Hopefully this has help provide more context that APIs are not the latest in vendor technology, it is just a newer approach to how businesses, organizations, institutions, government agencies, and individuals share information--one that leverages the technology we already have in place to support our websites.