> Or that I’m looking up a data point that I already actually know, just because I want to provide a citation.

Or what were know has changed.

When I was a child we knew that the North Star consisted of five suns. Now we know that it is only three suns, and through them we can see another two background stars that are not gravitationally bound to the three suns of the Polaris system.

Maybe in my grandchildren lifetimes we'll know something else about the system.

Well we should first establish some sort of contract how to convey the "I feel that I actually understand this particular piece of information, so when confronted with it in the future, you can mark is as such". My lines of thought were more about a tutorial page that would present the same techniques as course you have finished a week prior, or news page reporting on an event you just read about on a different news site a minute before … stuff like this … so you wold potentially save the time skimming/reading/understanding only to realise there was no added value for you in that particular moment. Or while scrolling through a comment section, hide comment parts repeating the same remark, or joke.

Or (and this is actually doable absolutely without any "AI" at all):

    What the bloody hell actually newly appeared on this particular URL since my last visit?

(There is one page nearby that would be quite unusable for me, had I not a crude userscript aid for this particular purpose. But I can imagine having a digest about "What's new here?" / "Noteworthy responses?" would be way better.)

For the "I need to cite this source", naturally, you would want the "verbatim" view without any amendments anyway. Also probably before sharing / directing someone to the resource, looking at the "true form" would be still pretty necessary.

Some people think the sunglasses in They Live let you see through the propaganda, others think that the sunglasses themselves are just a different kind of pysop.

So, you gonna “put on those sunglasses, or start chewing on that trashcan?” It’s a distinction without a difference!

https://www.youtube.com/watch?v=1Rr4mQiwxpA

Not any more "sentient" than existing LLMs even in the limited chat context span are already.

Naturally, »nothing new of interest for you« here is indeed just a proxy for »does not involve any significant concept that you haven't previously expressed knowledge about« (or how to put it), what seems pretty doable, provided that contract of "expressing knowledge about something" had been made beforehand.

Let's say that all pages you have ever bookmarked you have really grokked (yes, a stretch, no "read it later" here) - then your personal model would be able to (again, figuratively) "make qualified guess" about your knowledge. Or some kind of tag that you could add to any browsing history entry, or fragment, indicating "I understand this". Or set the agent up to quiz you when leaving a page (that would be brutal). Or … I think you got the gist now.