There's an old theory that big brands climbed to the top of google's search results because they consistently got more clicks than the sites above them in the rankings.
Of course the idea that CTR affects rankings has been around since the very early days of google. On the other hand, in past discussions here some members have categorically denied that google uses any kind of user behavior as a ranking factor. {Supposedly Matt Cutts essentially said this about 10 years ago.]
But I've always had doubts about this. It seems to me that data on user behavior would be a gold mine of useful information about how users perceive the value of a webpage. In fact, according to some reports at the time, google mainly created its Chrome browser in order to be able to collect detailed data on user behavior.
At any rate, I've noticed a recent change in rankings that could support the argument that google's algorithm actually does take account of data on user behavior. Specifically, for years a certain blog post from 2010 has ranked number 1 in google for a particular search term that I watch. But when I checked about two weeks ago it had fallen to number 2, and I also noticed that the date of the blog post {March 9, 2010) was shown in the search results, whereas previously it wasn't shown.
I checked again today, and this post has now fallen to number 3 in the rankings, with the date still being shown.
So this blog post had ranked number 1 for years, but when google started showing its date in the search results, it began falling.
This suggests to me that it began getting less clicks when searchers could see how old it is. And when it began getting fewer clicks, it started falling in the rankings.