Update README.md

Author: bdougie

README.md

@@ -1,9 +1,14 @@
 # Netlify Identity Widget
 
-A component used to authenticate with Netlify's Identity API. [Live demo](https://identity.netlify.com)
+A component used to authenticate with Netlify's Identity service. [Live demo](https://identity.netlify.com)
 
 For a lower level library to the underlying `GoTrue` API, see [gotrue-js](https://github.com/netlify/gotrue-js).
 
+## What is Netlify Identity
+Netlify’s Identity service is a plug-and-play microservice for handling site functionalities like signups, logins, password recovery, user metadata, and roles. You can use it from single page apps instead of rolling your own, and integrate with any service that understands JSON Web Tokens (JWTs).
+
+Learn more about this service from this [blog post](https://www.netlify.com/blog/2017/09/07/introducing-built-in-identity-service-to-streamline-user-management/).
+
 ## Usage
 
 Simply include the widget on your site, and things like invites, confirmation codes, etc, will start working.