Danny Sullivan of Google confirmed on Twitter that the search company launched the subtopics ranking feature or algorithm in Mid-November 2020, just weeks after announcing it at the Search On event in October 2020.
According to the announcement, Subtopics is a machine learning or a way for Google to understand subtopic around an interest, which helps deliver a greater diversity of the content when you search for something broad. For example, when anyone searches for a treadmill online, Google can now understand all the relevant subtopics such as budget equipment, small space ideas, and show a wide range of content for you in the SERP results.
Google used a GIF to illustrate it, but it cannot be illustrated:
Danny also explained on Twitter “subtopics don’t change the look of search results, only broaden the diversity of content, when useful.”
Well, yes or no. But Google did not confirm any ranking updates in mid-November, it just got confirmed from Danny that subtopics rolled out then.
If you also noticed any changes in mid-November, it may be related to subtopic ranking rolling out. There is rarely anything that you can change on your website due to subtopics rolling out in November 2020. This update is all about Google finding more relevant content on the web and providing result according to the relevant queries.