Can you tell me the age of my users?
I once had an onboarding call with a client where I was asked:
"Can you tell me the age of my users?"
I'm an engineer at an analytics company, and upon getting asked that question I was immediately taken aback.
It sounded like such a stupid question - how could we possibly infer that?
And then it clicked: this client was migrating off of Google Analytics.
You see, Google can and does provide age information in their analytics dashboard.
They can do that because countless websites across the world use Google Analytics and even more people use Google services.
Google can then cross-reference all the data they get and spit out a reasonably accurate guess as to the age of the users that go to your website.
Not only that - Google is not an analytics company. They're an ads company.
So the same model of your users from which they derive some of the information that appears on your dashboard is used to do very targeted advertising all across the web.
And that's ultimately the problem with Google Analytics particularly.
We can discuss the nuances of GDPR, sending data to servers in other countries, etc.
But at the end of the day, the biggest problem with Google Analytics is that it is a service provided by a company whose end product is not analytics.
So, from a user privacy perspective, you're probably better off with a company that provides analytics as their core product, however that's done.
Please note that I'm a very biased source. I work for PostHog, a company that isn't a direct competitor to Google Analytics per se, but also kind of is.
But my argument here is that, as long as you're compliant with local laws, you could switch to a cloud-based service like Mixpanel or Amplitude and it'd still be an improvement. Even though, as you'd expect, I'm an advocate for self-hosted analytics.