It was a little later than expected, but Google has officially rolled out their December Core update for 2020.
While Google is always making small and marginal changes to their search algorithm on an ongoing basis, they also tend to have a few large rollouts once or twice a year. These are either new modules for sorting (like Panda, Penguin, and some of the other "independent" algorithms) or major updates to the functionality of the core web algorithm.
This latest update has been confirmed as a core update and Google has some notes on what, exactly, that means:
https://developers.google.com/search/blog/2019/08/core-updates
Several times a year, we make significant, broad changes to our search algorithms and systems. We refer to these as "core updates." They’re designed to ensure that overall, we’re delivering on our mission to present relevant and authoritative content to searchers. These core updates may also affect Google Discover.
We confirm broad core updates because they typically produce some widely notable effects. Some sites may note drops or gains during them. We know those with sites that experience drops will be looking for a fix, and we want to ensure they don’t try to fix the wrong things. Moreover, there might not be anything to fix at all.
Google also suggests a number of on-page and technical improvements that may assist webmasters who see negative results during a major algo update. They also note that a drop in traffic after a major update doesn't even necessarily mean that your website has done anything wrong. It may just mean that some links you have used to carry more weight than they do now.
December Core Changes
While it can take two or three weeks for a Google algo update to fully go live, many webmasters are already seeing major changes. So far, none of my own websites seem to be performing much differently than before.
The sites around them in the SERPs do appear to be moving rapidly, however.
Here are some trends I've observed (non-scientifically):
- Sites with a large number of referring domains and questionable backlinks dropped momentarily before recovering
- Sites with a lower number of referring domains but just as many questionable backlinks dropped all the way off the board
- Sites that have focused on on-page and technical SEO have fared well
- Places that rank well on Google maps may be tied to websites that rank poorly