And GA4 is so GOOD – because of so many things, but not the least of which is that current machine learning makes life so much easier than old school thinking and processing. One word, ‘Insights’. Now they just show up on the home page and they are smart and awesome.
Finding this insight has been possible for almost always with alerts in UA. And there are even ways to make these old school alerts better. But going very old school, there was the great ClickTracks’ (yeah, mentioning it again, but for a good reason) report, the ‘What’s Changed‘ report which was on-demand anomaly identification.

So back in 2008, you could automatically see statistically significant changes in two dates or date ranges that you picked (not just in keywords, but many things. You should really read this article!). But now Google provides you those anomalies automatically in Insights. And you can even customize the thresholds for specific conditions.

Now you can combine automated machine learning insights with customized insight alerts tailored to your company’s very specific goals.
ClickTracks said ‘What’s Changed?’ back in 2008. I say, in 2021, , ‘a whole lot’.