After looking at some initial data for Google's December 2020 update, the general consensus is this one was big.
As powerful as the update was, wouldn’t it be nice to know what happened? What did Google change? What were they looking for? Why did some sites win while others saw ranking losses?
These are great questions and if you want exact answers, there aren’t any.
In this is a post I attempt to find themes within the update by qualitatively analyzing some of the pages Google swapped out on the SERP.