I don't think there is any website I care about checking regularly that does not have an rss/atom feed. All wordpress (and pretty much every other blog engine) sites do, subreddits do, https://hnrss.github.io/ for hacker news...

That said, I personally only use rss for slow-updating sites (pretty much just for personal weblogs and the news/announcements for some projects).

Quite common, most things that I try to subscribe to have a feed, including mainstream stuff like NYT, Axios, FiveThirtyEight, and smaller independent blogs. When one doesn't exist you can often use a Twitter feed instead (for the moment), but I've only had to resort to that once or twice.

Pretty common if not necessarily advertised. I'll echo what others have said-- any site I particularly care about has an RSS feed.

I've written scrapers for some things that don't expose RSS to dump into the tt-rss database, too. Having the data sitting in a relational database makes it easy to interface with. (I wrote my own "podcatcher" since 2005-era tt-rss didn't have any such functionality and just use the tt-rss database as its back-end.)

It is probably less than years ago, but its still a thing. In fact i heard youtube and other big sites (e.g. Reddit, etc.) still have rss feeds. Someone also told me that there is a bit of an uptick....buit this kind of thing is likely difficult to concretely quantify. As a single data point, I'm a fan of sites with RSS feeds...so i will frequent these sites more, and would be williung to pay for sites to have such a feature!

Quite common. However the Docker Blog recently changed their site to not have it so buh bye to them I guess.