It is not about having your particular data. Is about the aggregated data of a population. On a shallow level that information can be used to engineer ads to appeal to a greater audience. On a deeper level, population dynamics can be used for nefarious purposes such as driving them to an agreement that wasn't in their best interest. Brexit and the Trump election are two examples of this being possible thanks to data from Cambridge Analytica. See voting paradoxes and Asimov's psychohistory that each day is getting farther from fictional.

Money.

Your data can help sell you stuff. If they know you’re into MILFs, they can sell advertising to the MILF companies. Then you see a bunch of MILF ads. The more they know, the more they can target you. Eventually we’ll have ads in our dreams like in Futurama.

The more they claim they know about you the more they can charge for ads. I have recently realized that Google, Facebook and such are not only powerful because they aggregate data, but rather because they can sell their product (=your attention) to other companies very, very well. People often claim companies would not pay for advertisements had they didn't work — I claim otherwise; they pay for advertisements because Google falsely claims how effective they are and that's why they need to collect your data and be able to show that to their customers to boost their (Google's) sales. In other words they don't do that to sell the customers product well (the one that has been advertised) but rather sell their own product, which is ad space.

Do you have money? If so, knowing all your secrets and quirks is a good way to get a dollar off of you for slightly less than a dollar.

Why are tech company's

They're trying to track the patterns of people who attempt to pluralise words by using apostrophes. It's funded by linguists studying language change.

Wall of text, I know, but I had trouble sleeping so... Yeah... Here goes;

Knowledge is power.

Here in Sweden there's a service that has been pouring money on marketing the last two years. The service is called House ID and they let you store all important documents about your house for free.... Free... Free?

So what will they make money on?

Well, let's jump 10 years into the future and just imagine the possibilities.

Criminals can easily check what house owners have upgraded their locks or purchased home alarm systems. They could even purchase data about all the houses in an area that has a specific lock type with a known flaw.

Your phone is, with all its sensors, a fantastic surveillance device and people happily take it with them wherever they go.

In the 90's, when I worked for IBM, the buzzword was "Data mining". Ordinary people never understood what it was and I was often asked about it. Extremely simplified: look at the data you have and try to read between the lines to generate data that you originally didn't have.

The biggest chain of convenient stores in Sweden launched banking services and a pay card around this time. If you used the card for grocery shopping you'd get a monthly bonus and great offers and discounts. So I gave an innocent example of what your purchase data could be used for. They could see that a woman purchased pads on fairly the same time each month or quarter. Now, when cross checking this with purchase history from other women they could see that a lot of those women also purchased chocolate at the same time they purchase pads. Something something with a lot of women getting cravings of chocolate around the same time each month. Yes, it's a generalization but still a real life example in this case. So they sent out coupons for chocolate, matching the time around when the customer normally purchased pads, and what do you know? The sale of chocolate increased. Significantly.

Now, pads isn't a very sensitive subject of you're older than 15... But think what data Tinder registers. They can't know for sure if you're liberal, conservative or even a communist... or can they? By looking at your behavior in their app, what you did, where (Tinder uses GPS, remember?) you did it and when you did it, they can draw conclusions about a lot of things that you never intended to share with them.

Today there are sensors placed strategically in shopping malls that registers what store windows you stopped to look at. They actually know, with a pretty high certainty, exactly what product in the window that caught your attention. How they can be so accurate you say? Because you have Bluetooth activated and the mall app installed. They just triangulate your exact position.

All of this is data about you that is correct. You did all of that and it was registered.

But what if corrupted data was registered? What if that data was the basis for you getting a loan for your dream house? How do you correct a conclusion that is obviously wrong when the bank just tells you that what data they purchase, from who and how they process it is a business secret and they refuse to share any details.

Now, all sorts of data has always been collected but in the old time it was stored on paper and cross comparison/compiling data was an expensive and tedious task. Today it is not. Today your phone could store and process data that would take months to process in the old times.

That slowness/inertia acted as a law of nature, protecting us and our life from being mapped.

It's not just that data is collected or what data is collected... It's what it might be used for that should bother you. Not only what is used for today but also what it could be used for tomorrow.

Fun story: me and my wife kept talking about our nasty neighbour we call "the slug" and she got "Slug removal tips" on her YouTube suggestions.

Q: "Why are companies ..."

A: Money.

Every time. Sometimes also some competitive advantage or image or by mistake, but even those are just money with extra steps.

It all comes down to targeted advertising. They'll cluster you and other people with similar interests in groups, determine statistic likelihoods of buying/using/subscribing to certain products or services, and then blow up every channel with stuff you might like.

Maybe a MILF hunter with mild dyslexia is exactly the right audience for cat food and entry level red wine?

Because your data is used to make models of your behavior and opinions. Once someone knows exactly what you do and don't like it's really easy to frame purchase and political decisions so that they sound like something you want, even if they're really good for someone else.

they’re interested because they profit from the marketing based on the data

Because digital advertising dollars has been in a bubble since click-through ads and for some reason nobody has noticed.

To put it succinctly they aren't. They're interested in aggregate data so that a data engineer can use it to understand consumer trends and better predict marketing reach.

It's not specifically about you, it's more of a what they can claim to know about their consumers.

How much do FANG companies pay for such posts? I'm interested in making a career.

Pixar seeing a rise in milf web searches: Ok boys it’s time to release another movie with a mom who has a dump truck ass.

Pick up habits, profiling so they can know what you are interested in and the areas you frequent to target you more efficiently. More likely for directed advertising but can also be for influencing.

Why are tech companies* so interested

I can't find the source to save my life, but I believe it was a Google engineer who once said "with enough data, every problem is a regression problem".

They are interested in your data because you are human and you do human things, the more they understand you and your activities the better they can gather knowledge for economical decisions such as Ads, Trends etc.

Most commonly they use this information to manipulate you into using their services or changing your preferences by marketing and Ads. The more they understand you the more effective it is.

A spooky thing I noticed at one point I could search a rather vague query and Google was returning results in the programming language I was working with when the query was general enough to have been any language.

The single raindrop never feels responsible for the flood

Because the last bastion of zombie capitalism is pushing money around.

Folks buy this information because there are other folks willing to buy this information. And so on... and so on...

$$$

Other companies are willing to pay big money for your data so they can specifically target people who are likely to buy their shit. Also, now the government is buying that data so that they can unconstitutionally keep tabs on every person in the world.

You have ass data?

The simple answer: the more they know about you the more money they can make by selling it.

this article has some insights on the value topic.

this Reddit post also has some good information regarding this subject.

Lastly, this scandal

I hope this helps, please feel to correct me if I’ve misunderstood something.