[Johnny555]

I guess it could be some honor system "pay when you leave". Or maybe let you review the article "Was this worth 8 cents to you?" and display the votes before you pay so you can decide if it's worth the money. Or maybe you can flag an article as clickbait and get your money back.

[w-ll]

Could it be a function of time on page, maybe even with scroll distance. You generally know if the article will be garbage in the first paragraph or two and always before the fold (doubly so before the fold if there wasnt ads taking up the top 75% of the page)