In that CNBC article, Google told them that in 2017 Google ran 31,584 side-by-side experiments with its raters and subsequently launched 2,453 search changes. Of course, the “2,453 search changes” can be small design tweaks and such. Google does not disclose the number of algorithm changes. The article added “While changes can have enormous effects on how any given website is ranked – and thus the amount of people who see it – regular Google search users often don’t notice the changes at all.” Yes, most the changes, most people wouldn’t pick up but as you know, we’ve covered tons of them here – I know I don’t cover them all. We cover many of the Google algorithmic updates and the Google user interface updates. Most go unconfirmed, but we try out best to cover them. We did not cover all 2,453 changes but we did cover some of the 31,584 experiments that did not go live. I suspect most of these changes we don’t even catch. But again, I also suspect that of the 2,453 changes, less than 10% of those are related to the core web search algorithm. But that is just my wild guess. Pedro posted a while back some of the number of changes Google documented over the time, I am not 100% if this is accurate but it brings things in perspective – that Google is busy: Forum discussion at Twitter.