What Tech Knows You is
Tech Knows You is a small public-awareness piece about a very large number. The world spends roughly one trillion US dollars a year on advertising, and around $800 billion of that goes to digital channels — the feeds, search results, videos and web pages you move through every day. Spread evenly across the year, digital advertising burns about $25,000 every second. Around the clock. Including right now, while you read this sentence.
Numbers that size don't mean anything in the abstract, so we make it personal. The grid on our home page contains four live ad slots, served by Google's ad network and personalised — by Google's systems, not ours — to whoever is looking at them. The ads you see there are the actual output of that trillion-dollar machine, pointed at you, at this moment. They are not a simulation, a parody, or a curated gallery. They're the receipts.
We call it "what the algorithm thinks of you" because that's genuinely what it is: a live read-out of how the ad-targeting machinery has profiled the person holding the phone. Sometimes it's eerily accurate. Sometimes it's bafflingly wrong. Both outcomes tell you something about how you've been categorised — and both make a pretty good screenshot.
How ad personalisation actually works
When a page with ad slots loads, an auction happens in the time it takes you to blink — usually under 100 milliseconds. The ad network looks at signals it has available: the rough context of the page, your device and language, and — if you've consented to personalised ads — interest categories inferred from your activity across the web, past searches, the kinds of sites you visit, and demographic guesses built from all of the above.
Advertisers, meanwhile, have told the network who they want to reach: "people likely to be shopping for running shoes," "small-business owners," "recently moved house," "in-market for a compact SUV." The auction matches their bids against the profile of the person loading the page, the highest relevant bidder wins, and their ad renders. Multiply that by hundreds of billions of impressions a day and you get an industry that runs more auctions in an afternoon than every auction house in history combined.
The crucial point: nobody at the advertiser knows it's you. They bought an audience segment; the machine decided you belong to it. The profile is the product. Tech Knows You just puts a frame around it.
What we can and can't see
This part matters, so we'll be precise. The ads on Tech Knows You render inside Google's own sandboxed frames — a hard browser security boundary. Our code cannot read, capture, store or re-serve what's inside them. We never know which ads you were shown. We don't have accounts, logins, analytics profiles or a database of visitors. The only thing that travels when you share a link is the caption you typed, carried in the URL itself.
That's also why sharing on Tech Knows You works the way it does. The wrapped card you can make is built entirely from things you supply — the tags you pick to describe your ads, your caption, and the live counter — drawn on your own device and never from the ad creatives themselves (we couldn't copy those if we tried). And if you want the actual ads in the shot, the only technically possible route is the one we offer: a plain old phone screenshot. We think that's rather fitting. The one party in this whole pipeline who can capture what the algorithm thinks of you… is you.
Why the number matters
Advertising spend is one of the clearest measurements that exists of what your attention is worth. Roughly $140 of digital ad money is spent per internet user per year — more in wealthy markets, much more if you're in a coveted demographic. That money pays for most of the "free" internet: the search engines, the maps, the video platforms, the news you didn't pay for. It's not a hidden conspiracy; it's the published business model, with quarterly earnings calls.
But the scale stays invisible because it's deliberately frictionless. You're never shown the bill, the auction, or the profile — just the winning ad, woven into your feed as if it grew there. Tech Knows You reverses the polarity for a minute: instead of ads interrupting content, the ads are the content, labelled and lit like exhibits, with the meter running in plain view above them.
If you're not paying for the product, you can at least look the pricing in the eye.
The irony, acknowledged
Yes — this site about ad money is itself funded by ad money. The four slots in the grid are real ad placements, and when they fill, Tech Knows You earns the usual fractions of a cent that any page earns. We're not embarrassed by this; it's the point. There was no way to show you the machine without plugging into the machine, and pretending otherwise would be the only actually dishonest option. Consider it a tasting menu funded by the kitchen.
What we will never do: encourage you to click the ads, refresh in a loop, or game impressions. The grid is for looking at, thinking about, and screenshotting. The refresh button exists so you can get a fresh read of your profile — it deliberately cools down between uses.
A note on "the algorithm"
We say "the algorithm" as shorthand for the ad-personalisation systems that decide which ads you see. The grid on Tech Knows You is served by Google AdSense; the targeting, the auction and the creative selection are all theirs. Tech Knows You is an independent project — not affiliated with, sponsored by, or endorsed by Google or any advertiser who happens to appear in your grid. If the algorithm thinks you need a stair lift and a gaming chair in the same breath, take it up with your browsing history.
Who made this
Tech Knows You is a small independent project. No accounts, no funding round, no growth team — just a page, a counter, a grid, and the hope that you'll wrap your read and pass it on. Questions, corrections to our figures, or press: [email protected].
Our methodology and sources for the spend figures are published on the home page, and our data practices in full in the privacy policy.