A long time ago, somewhere around 1995, Apple engineers came up with the idea of a specification for describing the structure and content of a website. They called it Meta Content Framework. The plan was to build powerful 3D site navigation on top of it, like in cyberpunk. The idea didn't take off, but one of the authors moved to Netscape and developed it there into the Resource Description Framework (RDF), whose first R also happens to be the first letter of RSS.
RSS has three different expansions, but the essence is the same. It's a way to get articles from websites. You can subscribe to interesting news, blogs and articles, and read them in a dedicated app. In the golden years of RSS, linking to a feed was good manners for any platform or publication. Readers came as standalone apps, were built into browsers, and Google had a whole Google Reader. The format peaked somewhere around 2005.
And then the world moved on. Facebook came with its algorithmic feed, and publishers decided they didn't like sharing content for free. The web became centralized. RSS went into decline. By the time Google shut down its Reader in 2013, only fans were still using the format.
Now the world is moving again. Endless feeds drive people crazy. Facebook and YouTube ban whoever they want. Twitter sells blue stickers. The most freedom-loving tweeters have already crawled over to Mastodon and write toots instead of tweets. Everyone who has put enough effort into their profile, blog or channel wonders who owns the results of their work and whether it'll all be wiped out without explanation. Content creators are moving to standalone blogs. The web is fragmenting.
This is all sad, but there are upsides too. It looks like soon we'll be able to take good old RSS off the shelf, gather interesting articles from different sources in one place, feed them to a GPT model to cut the noise and write a tldr, and read. Here Feedly talks about their AI. And here Readwise invites you to try the beta of their reader with RSS support. Give it a try =)