I think, the uBlock Origin context menu does that?

> Just read the webpage as it is rendered to an actual human

Humans read web pages using their vision. So what you’re proposing is to look at the final rendered image of text instead of the DOM tree. The only way to do that would be to perform OCR (https://en.wikipedia.org/wiki/Optical_character_recognition) on a screenshot of the whole web page. This would be possible, but I think nobody’s tried because it feels overly complicated, and many OCR libraries can’t understand text 100% reliably, not even computer-rendered text. Also remember that the OCR library would have to run in JavaScript. Would it run fast enough to block the ad before the user sees it? Would it annoy the user by spinning up their computer’s fan?

> identify the x/y coordinates of the element

This wouldn’t be too too hard to implement using `document.elementsFromPoint(x, y)`. This part isn’t the problem.

I'm not sure that facebook does it for the "promoted" text, but they have been known to mess with layout to make text difficult to detect. For example each character of a word might be in a separate <div> and be strangely offset so as to line up. The divs might not have the mutually common parent element that you would expect.

The browser has no context for what it is rendering. Should it ban every element containing "promoted"? Even posts by people?

The word "promoted" might not even appear as text, it might be simply a series of divs with one letter each (out of order, of course) and then visually defined with CSS.

The browser doesn't know it's rendering a word, it only knows it's rendering a series of divs with one letter on each, and it absolutely can't know what the visual representation of the divs spell.

What you are proposing is another crazy AI solution, OCR.

Which would mean to render the document, using pattern recognition delimit the area with the sponsored post, then pass those coordinates to the browser in order to select the currently visible element, then delete it.

Even then I could think of a thousand ways to beat this, because OCR can't see invisible things and you can do all sorts of fun stuff with invisible styling, and it'd be the same game of cat and mouse the ad blockers are currently running but at a higher level of abstraction.

I think the issue isn't finding the text "Promoted", but coming up with a way to figure out exactly which element containing that text to remove (because simply removing the text itself would not be a good solution). I imagine that Facebook could be doing something like generating a CSS class names on based by using a different seed or producing different element configurations that visually appear the same for each page load (or worse, for each ad on the page...)