It sounds simple on the surface. You copy a link on a site into a feed reader app. Then whenever that site updates you get a nice readable article on the app.
But that sounds like something that could be accomplished locally. Why does every RSS reader I run into require an account or otherwise rely on the cloud?
RSS feeds are incredibly useful, I use them to keep up with all sorts of news. Most feed readers also let you group different feeds into categories. I have mine divided between science, technology, world news, etc.