Axios also puts this to great use with a "go deeper" button. It's very helpful for deciding how much of each story to consume.
Screenshot: https://i.postimg.cc/SKkKc85H/Screen-Shot-2018-12-10-at-11-5...
Screenshot: https://i.postimg.cc/SKkKc85H/Screen-Shot-2018-12-10-at-11-5...
On one hand, forcing users to click a button to see content is kind-of user-hostile, IMO. It's appropriate for a homepage, though. I don't like it when a homepage shows the full content of each post because it forces me to do a lot of scrolling if I'm not interested in a post. So my first impression is that Axios is doing it well and thoughtfully.
But on the other hand, the interaction enables me to track what percentage of users actually care about the content, which is really useful data to me as a documentation author. I'm not saying we should do it --- I'm firmly on the "put the user first" side of the debate --- but I just wanted to point out that the current state of documentation is kind of a dark age. We have no idea what our readers actually care about.
I do track the other interactions you mentioned, but it's difficult to map them to actionable ways to improve quality. And then even if we do make them actionable, it's hard to prove that they have actually improved quality. I'm just starting out a rigorous study of this field, though, and am hopeful that we can make advances.