> It ought to be able to work out who your close friends are, and what kinds of things you normally click on, surely?
I wish this didn't even seem right to anyone, even from the beginning. It's different whether I happen to click or be interested in something once than it being what I want to see again. If I go to a movie, that's not evidence that it's my sort of movie — I don't know if I'll like it until I see it! Priority really has to be on the evaluation of things and the explicit desire to get more, not on reading things into the fact that I was open to something in the first place.
With the what-I-click approach, one day I am prompted for some reason to click one sort of thing… then I'm shown that more the next day… then one pretty-arbitrary starting point is turned into a defining filter for me forever. This reality means that simply clicking something out of curiosity threatens to define you and your experience for years.
The ethical way to handle this is to do some mix of (A) giving back control to the readers for what they explicitly choose to follow (not whatever they happen to click, and not even what they "like" because liking should not equal following) and (B) doing the opposite of bubbling and actively insert some mix of stuff-they-don't-usually-click, i.e. novelty so that people are actually exposed to new ideas and perspectives they might otherwise not even know exist.