There is a small confession booth built into every ad you see, and hardly anyone opens the door. On Google’s properties it hides behind the three dots, or the little “i”, in an ad’s corner; on Facebook and Instagram it’s the three dots, then Why am I seeing this ad? Click it and the machine, for once, is obliged to explain itself. The explanation is partial, sanded smooth by lawyers, occasionally absurd. It is also the nearest you will get to reading your own advertising profile: the version of you that gets auctioned to advertisers in about a tenth of a second, every time an ad slot loads.
So this is a field guide. Two stops — Google’s My Ad Center and Meta’s Ad preferences — with detours into what the settings actually do, what they conspicuously don’t, and why the file the machine keeps on you manages to feel like surveillance and satire at the same time.
Google: the filing cabinet
Start at myadcenter.google.com, signed in to your Google account (the older adssettings.google.com lands in the same place). The front page shows ads you’ve seen recently across Google’s services, plus the topics and brands the system currently believes you care about; you can ask for more or fewer of each, or block a brand outright. That part is decoration. The good bit sits under the privacy controls, where Google lists the categories it may use to personalise your ads: your age bracket, the languages you use, whether it thinks you’re in a relationship, your education level, your household income band, the industry you work in, whether you rent or own, whether you’re a parent.1
Read that list slowly. You never filled in a form titled “household income”. These are inferences, distilled from what you searched, watched, installed and visited, then sorted into a taxonomy tidy enough to sell. Say you watch three sourdough videos in January: somewhere in that catalogue you are now, durably, a baking enthusiast, and bakeries will pay a little more to reach you. The profile doesn’t record what you did. It records what you can be sold as.
Meta: the guest list
Meta’s equivalent lives in Accounts Center — burrow through Settings on Facebook, Instagram or Messenger — under Ad preferences.2 There are ad topics you can ask to see less of (gambling, alcohol, parenting and weight loss can all be dialled down; use that freely). There’s a control over whether activity that businesses share with Meta — the pixel on the shop you browsed at midnight — is used to aim ads at you. And there is my favourite document on the consumer internet: the list of advertisers who uploaded your contact details. Companies you may never have heard of, who arrived at Meta’s door holding a spreadsheet with your name in it.
Then there’s the affordance itself. Tap the three dots on any feed ad and choose Why am I seeing this ad? The explanation is generated by machine-learning models summarising which of your activities, on and off Meta’s apps, fed the targeting.3 It tends to read like a polite horoscope: you are over 25, you live in a city, you are “similar to” people who bought the thing. That word similar is doing enormous work. Often you’re seeing an ad not because of anything you did, but because people who resemble your data once bought something.
What the toggles do — and don’t
Both companies let you switch off ad personalisation entirely, and the switch is real. Flip it in My Ad Center and Google stops using your account activity to pick ads on its own services and on partner sites; your saved topic preferences are deleted; ads fall back to general signals like the time of day and the subject of the page you’re on.4 Meta’s controls work along similar lines. This is contextual advertising — the model the web ran on before the auctions got personal — and there’s a case that it’s the more honest one.
Now the caveat that the settings pages state plainly and everyone mishears anyway: turning off personalisation does not mean fewer ads. The slots don’t close. The auctions still run. The same inventory gets filled, only now it’s addressed “to whom it may concern” — which, in practice, means the same handful of broad-reach campaigns on heavy rotation. Nor does the toggle stop data being collected; that lives in separate activity controls. What you’re switching off is one use of the file, not the file.
The choice on offer is never ads or no ads. It’s ads that know you, or ads that don’t.
The no-ads option does exist, but it’s called an ad blocker and it comes with its own argument. Within the dashboards, the decision is narrower and stranger: would you rather be misunderstood specifically, or generally?
The mirror with opinions
Spend ten minutes in either dashboard and you’ll meet the strange double feeling this piece is really about. The profile is right in ways that prickle: it has your age within a band, your city, your slow drift towards buying a bike you’ve mentioned to no one out loud. And it is wrong in ways that are almost touching. It thinks you’re in the market for a stairlift because you searched for one for your mother. It has decided, off the back of one insomniac binge, that you are passionately interested in competitive fishing. It cannot tell which of your searches were for you — a flaw with a much darker edge than the fishing suggests.
The profile is a mirror with opinions: it reflects you back, then argues for the reflection.
And here is the catch built into correcting it. Every fix is a donation. Tell the machine you are not interested in fishing and you’ve confirmed this account belongs to a live human who reads their file — a data point. Curate your topics carefully and you have hand-labelled yourself more precisely than any inference could. The dashboards are genuinely useful. They are not neutral. They are the one survey almost everyone answers truthfully.
$57
That, give or take, is the sum being argued over each time the mirror renders its opinion of you. This site is not outside the argument: the ads that fund it are chosen by exactly this machinery, aimed with exactly this kind of file — openly so. I won’t tell you whether to flip the big switch; that’s a temperament question. But do go and read the file. It isn’t you. It’s the machine’s best guess at what you might buy, wearing your face — and you should at least know what’s being said about you in the room where the prices are set.