So I wrote this pretty deep dive into how Google uses AI in Google Search at Search Engine Land, and Google posted a shorter version on their blog. I noticed after that, some folks were saying that Google uses MUM for search rankings. Truth is, Google uses MUM for only two things in search, COVID vaccine names and a related topics in videos results feature - that is it.
Google does not use MUM for ranking or improving search quality, Google reiterated to me when I interviewed them for the AI story. Now, the confusion I believe comes from Google and in some talks given by Googlers that may have misspoke but trust me, I asked this question numerous times and it is in the official blog post, Google is not using MUM for ranking.
Sure, this can change and I don't know if you remember, Danny Sullivan of Google told us that Google will let us know when they use MUM in search - but that has not yet come yet.
Google told me "MUM is not currently used for ranking purposes, it is currently only used for COVID vaccine naming and powers the related topics in videos results." Google's Pandu Nayak, a Google Fellow and Vice President of Google Search, wrote on the Google blog "MUM is not currently used to help rank and improve the quality of search results like RankBrain, neural matching and BERT systems do." He added "when they're deployed, they'll join the chorus of systems that run together to make Search helpful," but they are not deployed yet.
Here is how Google uses MUM right now:
COVID-19 vaccines naming:
Related topics in videos results:
That is all - really. MUM is not used anywhere else, yet. But when it does get used in more places, trust me, we will let you know.