Since I haven't tried this feature at all, the questions are simple but overwhelming: What does it do? How does it work in terms of notification? Is there just one feed or are there feeds per board and thread too? Are there also feeds per users? Has anyone tried it? Is the feature documented on some help page?

Having now approached the forum RSS at several places in several ways, it appears that it does just one thing: It features Most Recent Posts. Am I getting it right?

Looks like you can at least get it per board by adding ;type=rss;action=.xml;limit=20 to the URL.

https://thedndsanctuary.eu/index.php?board=1.0;type=rss;action=.xml;limit=20

(Other options are type=atom, rdf, and rss2.)

There's some more info here, but it must be based on an older version or something.

Looks like you can at least get it per board by adding ;type=rss;action=.xml;limit=20 to the URL.

Hey, this works for user posts too! You can subscribe to my postings!

The utility of RSS is to integrate feeds from many different sources, usually corresponding to our interests, so we can access new content from a variety of sources just at one place instead of needing to go at a daily basis to hundred of different web addresses.

For that, a feed aggregator, I use Netvibes for long time ago. It allows me to create how many tabs I want where I can group feed widgets of the same kind of content. For example, clicking in the tab "Bicycles" I can read each day all the new content from a variety of bicycle related websites and blogs or even forums.
Netvibes is a very graphical and customizable kind of thing so some of you more concerned with "text, no images" will probably don't like it.

At one particular time, still with D&D, I decided to add the forum there. Honestly I didn't like it because the idea of a forum is not just to read but also to post, something that you can't do through a RSS feed, and kept maintaining  D&D out of the RSS system as a stand alone website.
So, basically I read DnD at DnD and almost everything else from my daily web routine at Netvibes.

Besides, I think, not sure, that my traffic will be just between my pc and netvibes, so outsiders can't make analysis that I didn't asked them to do.  Course netvibes can but, at least, they're French not from the land of NSA.
There are certainly other products that does the same but I only know this one.

You know what? Facebook may be considered a host "containing" such an aggregator. Or rather up-to-user possibility to create such.
Apart from their usual "home" page (or the newer "Pages" page), there is a tool named "interest lists": you can create multiple such lists - on different topics -- and then you will be able both to share them lists - AND COMMENT TO INDIVIDUAL STORIES in them - unlike what you described, Bel (which I appreaciate).

Hey, this works for user posts too! You can subscribe to my postings!

I can't quite seem to figure out how? But no matter, frankly that'd be a bit creepy.

Glad to creep you out https://thedndsanctuary.eu/index.php?action=profile;u=14;type=rss;action=.xml;limit=20

You know what? Facebook may be considered a host "containing" such an aggregator. Or rather up-to-user possibilty to create such.

I don't think so, totally different concepts and tools for different objectives. However, since I'm not familiarized with Facebook I can't say too much about it.

There's something that you can do with Netvibes, you can set your "page" as public (instead of private, as I do). That's the maximum you can interact with other people, in the sense other people can also see your collection of feeds about some theme you put there. Useful for a community of people with the same interests, for example.

You can have a private page and a public one if you want but the content will be always either feeds or utility widgets. No "likes" or lists of "friends".

Nah, now I see the user subscription doesn't really work. I thought it showed my posts, but it showed because my own posts were latest, me being so nuttily active here.

Any way I try it, RSS only shows Latest Posts. By having the board number in the URL, it shows latest posts in that board. Picking any thread's URL in a board and trying to generate RSS from it, it again shows latest posts in that board, not in the thread. That's how it's made.

@Belfrager
I seriously prefer any local RSS client, not some web-based service. For the same innumerable reasons why I prefer an email client over webmail.

Another note on this stuff.

This URL https://thedndsanctuary.eu/index.php?action=unread
and this https://thedndsanctuary.eu/index.php?action=unreadreplies
respect the user choice of blocked boards and blocked users.

RSS https://thedndsanctuary.eu/index.php?action=.xml;type=rss shows Most Recent Posts and doesn't care about blocking. So it's useful when you want to take a sneak peek past your own blocked stuff

I seriously prefer any local RSS client, not some web-based service. For the same innumerable reasons why I prefer an email client over webmail.

You are right. If you are simple.

Because if not, web based services are a good way of getting a lot of info, without any trouble, but just having a strategy which is a very simple one. Put into web services everything that makes you seem equal to the multitudes.  Build up your gray profile, just like millions.

What difers you from the multitudes, you keep for yourself, no web services. And use Thor.