RSS is a web feed format with a complicated history, which makes defining it precisely a bit tricky, but the gist of it is: it's a bit of XML served over the web that describes an information feed. In non-technical terms, it's a web page that you can query fairly often and that contains new content that you might care about. In practical terms, you add a bunch of links in a program called an RSS reader and content gets served directly to you as it is published.
I believe that RSS is good™ and that more people should use it, both content consumers and producers (btw check out my own feed).
One of the biggest arguments for RSS feeds (in my opinion) is that they are decentralized. Instead of getting your feed from Twitter, Facebook, Reddit, YouTube or any other big social media platform, you get it directly from the content producer.
This has lots of advantages: censorship simply doesn't apply as there is no middleman, content is distributed directly (there's no big scary algorithm to please), there is no data collection from big tech and no single point of failure (if one site goes down, only that bit of your feed will be unavailable for a little while).
On the other hand, while the content itself is decentralized, the consumers use a single client. This is a refreshing change from having to check loads of sites/apps to get updates for all the feeds that you care about. In practice, the RSS reader becomes a one-stop shop for all the things you want to be updated about.
While decentralization is nice, most people still want to access content that is hosted on centralized platforms. Worry not! Many such platforms provide native RSS feeds that you can subscribe to.
You can turn any YouTube channel into an RSS feed by using links that look like this:
GitHub provides native feeds to track new commits, releases and more in repositories:
It appears that you can turn all kinds of Reddit URLs into RSS feeds. I haven't tried it myself as I don't use Reddit.
For platforms that don't provide native RSS feeds, there exist many services that will aggregate data themselves and expose it as RSS feeds. I won't recommend any as I don't have any experience with them, just research them if it sounds interesting to you.
Accessing centralized information via RSS is particularly nice because it shields you against many attempts at making your feed as addictive as possible. You won't get flashy notifications, FOMO-inducing designs, seductive thumbnails and an RSS reader is more likely to get out of your way than to try to get you to stick around all day: you can check it once in a while and be done with it.
If you want to give RSS a shot, all you need is an RSS reader and a few feeds.
There are all kinds of RSS readers, from browser extensions and online services that sync across all your devices to desktop applications and terminal programs. I can't vouch for anything that I haven't tried (I personally use Newsboat, which I like a lot, but isn't for everyone), but you'll find plenty of readers in your favorite app store/package manager's repos or by looking up "best rss reader $CURRENT_YEAR" for more than 30 seconds.
Here is a short unsorted list of feeds that I enjoy and that you might too:
Just have an endpoint which serves valid XML, that's it.
Many site generators will handle it for you, but if you want to do it yourself, simply taking inspiration from other feeds is going to be the most time-effective way to get started. Don't forget to add a link to the feed to you main site and you're done.
Note that your own RSS feed can be very free-form. You can link to any content anywhere, not just your own. I would encourage people to share articles that they didn't author, links to other feeds that they particularly enjoy and anything that you deem worth sharing. Of course, you might not want to spam the avid readers of your highly technical blog with every last update to your favorite toy-train-enthusiasts forum, but in my opinion, a little variety helps making the web more decentralized and fun.