RSS feeds are a way to see updates from across the Web in one place.
You use a feed reader app and plug in feeds, so you can stay up-to-date on all sorts of things—what your MP has been up to, but also headlines from your local paper, the latest from your favourite recipe blog, and so on. Kind of like the Facebook timeline, except you have way more control, and we don’t have to pay lots of money to Facebook.
In the 2000s—the teen years of the Web—they were really popular. When this site was created in 2010, they were a core feature. Since then, we've seen the decline of the open Web and the rise of centralised platforms like Facebook, Twitter, and Tumblr. RSS feeds have fallen out of style, and browsers no longer offer easy, default support for them. “Well,” says your site operator, shaking his fist at a cloud, “I still like them!”