What is RSS?
RSS stands for Really Simple Syndication or Rich Site Summary however it is often referred to as the feed or news feed.
All WordPress websites have a RSS feed and you can view it by going to http://site-domain/feed
RSS allows users to keep track of their favourite websites without having to manually visit the website each time and it allows publishers to automatically syndicate their content, so that people can read it in their mailboxes, feed reader and other devices.
How to use RSS Feeds
You can subscribe to RSS feeds using a feed reader such as Feedly which is available as a browser add-on as well as mobile app for iOS, Android, and Kindle devices. By using Feedly, you can sync your RSS subscriptions across your devices and resume reading wherever you left it. Adding your favourite websites to Feedly is really simple, just enter the url of the website and click the add button to subscribe.
How to promote your RSS Feed
Your WordPress website already has a RSS feed but you can help encourage people to subscribe to your RSS feed by adding an RSS icon to your sidebar or other area on your website.
You can burn your RSS feeds using a feed burning service like Feedburner or Feedblitz to get additional statistics regarding your feeds. There is some concern over the support of Feedburner since Google took over this service so you might want to consider other options.
Using your RSS feed to create newsletters
You can use your RSS feed to create daily or weekly newsletters in WordPress by using services such as Awber or MailChimp. Once you have set this up your newsletters will automatically be emailed out to everyone one your subscription list as frequently as you choose.
WPBEGINNER have a tutorial on how to set this up in Mailchimp:
Hopefully this has helped you to understand what RSS is and how it can be used either as it is or to create newsletters directly from your blog.