Ahoy matey
While the business world of the dotcom boom was preparing to burst, consumers were starting to learn that while waiting for an image to load on the internet was still slow, once it was on your machine, things were fast. Users started branching out into other media like music, and certainly not pornographic videos. The likes of Napster, Limewire, Kazaa, and people just torrenting things left and right, was a One Piece-level deployment of piracy unseen before on Earth.
And suddenly firstname.lastname@companywhohasmycreditcard.com wasn't such a great identifier.
Don't be evil
It's so hard some times to remember that the world may have once been any way other than it is now. In the early aughts the internet wasn't the ad-infested garbage pile it is now.1
Back in the mid-nineties if you wanted to share a website with someone, you wrote down its url on a piece of paper, and handed it to them in class. I remember vividly reading and copying the urlencoded equivalent of antidisestablishmentarianism into netscape's url bar, and hoping it didn't land me somewhere weird. To ammeliorate this pain for web denizens, various solutions arrived. One of these, was the humble search engine, and the best ones around were Yahoo, Google, AltaVista, and Ask Jeeves.
Thing is, Google was still private at the time, while the others were all public. So when the dotcom bubble burst and imploded the other three's valuations, Google was comparitively unscathed.

Now Google was still private for the same reason the bubble burst: lots of users, but no way to monetize them. All those companies that had just evaporated from the bubble bursting had the silly notion that people would "pay" for the services they provided. Google wasn't the first of course, but they were certainly the ones who went HAM on the idea of monetizing user behavior through advertising.
They started by putting ads on their search results page, but in 2003 they released the real money maker.2 Google's ad sense platform would let content creators drop some small snippets of code on their sites that would serve ads to users based on what the users search history. Serving relevant ads to users improved engagement, which was more profitable for Google, the company advertising, and the content creator...well at least at first.
Once the money faucet was turned on, Google's thirst for information became insatiable. Their motto, "Don't be evil" let everyone know just how innocuous their data collection was. Their plan was to release free services for the benefit of humanity, and for their troubles they'd just collect some data here and there.
In 2004, less than twelve months after releasing ad sense, they released the ultimate money making service: gmail.
By 2004, Yahoo, and Hotmail emails were decidedly uncool. And forget about it if you were still using aol. In fact most tech was pretty uncool since it put a bunch of people out of work just a few years before.
There was one cool thing though. In 2001 the soon to be largest company in the world had figured out a device for people to put all that pirated music on, and somehow convinced the world that if your headphones weren't white, you weren't even really listening to music.
Now the iPod was cool in large part because it was exclusive, and it was exclusive the old-fashioned way--Apple made it prohibitively expensive. Exclusivity in tech was a novel concept from the dotcom days of everyone and their brother being able to sign up for everything. So when Google launched gmail as a "beta" that people had to be invited to, it created exclusivity, and suddenly the decades old tech of email, long rendered useless by spam and garbage, was somehow cool enough again for everyone to switch.
Today about a quarter of all humans have a gmail account. I'll leave it to you how they're living up to their motto.3
So great, Google corners the market on one of the universally held identifiers out there. The other, of course, is your phone number. Seems fitting your next move would be to acquire a phone company right?
In 2005 Google acquired Android to do just that.
If you make your money from ads, I've got no beef with you. The ad-dispensing companies have made it their mission to encroach on your creative space as much as possible to extract value from your hard work. I'm here to help carve out a path to you making more money in addition to how you use the ad networks.
If you look at Google's P&L statements, you'll see that search comprises by far the largest part of their revenue. What I mean here by saying the "real money maker" is that the adsense platform is what put google into every nook and cranny of your internet, and allowed them to charge what they charge for knowing who you are.
When Google created a parent company Alphabet, Alphabet dropped the don't be evil. The don't be evil line moved to Google's code of conduct. I wanted to avoid inferring anything from this, but when you change something like don't be evil to anything else, it's worth a questioning glance.