Rather than splitting the PageRank equally between all links je a page, some links are valued more than others. There’s speculation from patents that Google switched from a random surfer model (where a fatiguer may go to any link) to a reasonable surfer model (where some links are more likely https://techonpage.com/story4747691/le-meilleur-c%C3%B4t%C3%A9-de-cr%C3%A9ation-de-backlinks