Every sale hands your details to an independent seller the platform says it does not answer for, and your browsing and purchase history is the advertising. “We do not sell your data” arrives beside a concession that the same flow may count as a sale under some laws.
A detailed purchase and address record. Worth listing.
Order and tax records are kept for years; marketing profiles linger until you object.
Checkout needs payment and address; ID is rare unless fraud is flagged.
Industry profile reviewed 23 August 2026. Also machine-readable via the free API.
What leaks is a list of things you never said out loud: what you bought, when, and the address it went to. Purchases imply diagnoses, pregnancies and beliefs you never declared. Gifts you sent put other people's homes in the file too.
Every sale hands your details to someone else
Buy something, and your name, delivery address, email and often your phone go to an independent seller whose conduct the platform commonly says it does not answer for. Sell and take payment, and the marketplace becomes a financial institution: government ID, date of birth, bank details, and, where the law requires, a tax file reported to the authorities.
Your purchase history is the advertising
What you browse and buy feeds targeted ads. Several policies say plainly they do not sell your data, then concede in the same breath that the same flow may count as a sale under US state law. Marketplaces also hand hashed emails and device IDs to ad platforms to find you, or people like you, off the site.
Kept as long as they judge necessary
Most policies keep your data "as long as necessary," or for the life of the account, with reasons stacked so one always applies, and almost none put a number on it. Fraud prevention is the exception that survives leaving: a banned account's records are kept precisely to stop you signing up again.
Worked out from the industry, not from any one company. What you actually handed over is yours to record.
Built only from what this kind of service actually collects. A dimension that the data does not support is not listed.
What and how often you buy estimates your spending power.
Purchases can imply conditions, pregnancy, or medication.
Two kinds of hold. LAW SETS IT: a statute makes them keep it. THEY SET IT: a ground the company grants itself.
To flag suspected fraud, often on a shared industry database you cannot reach through the company.
Tax and company law makes them keep billing and payment records.
They can keep records to defend a live or possible legal claim.
The ad market behind these sites is enormous: one marketplace's own cookie banner lists nearly 800 partners it shares hashed emails and device IDs with, and some buy profiles from data brokers too. The files are a proven target: a regulator penalised one marketplace group after finding it had stored card numbers in plain text and played down a breach of tens of millions of accounts.
Purchase history is prime targeting and resale data.
Buying patterns train recommendation and pricing models.
Anonymised is their word. Purchase histories are highly distinctive: four card transactions identify 90% of people (de Montjoye et al., Science, 2015).
Fifteen demographic attributes re-identify 99.98% of Americans in a released dataset (Rocher, Hendrickx and de Montjoye, Nature Communications, 2019); date of birth, postcode, and sex alone did it for most people in the first study of the problem (Sweeney, 2000).
Four card transactions identify 90% of people in payment data (de Montjoye et al., Science, 2015).
Language models infer where a person lives, their income, and their sex from their writing alone, at near-human accuracy and at scale (Staab et al., ICLR 2024).
Browser and device fingerprints were unique for 84% of visitors in the first large study (Eckersley, 2010), and sparse histories of what people viewed re-identified them against public reviews (Narayanan and Shmatikov, 2008).
THE STUDIES Estimating the success of re-identifications in incomplete datasets using generative models (Nature Communications 10, 3069, 2019)·Simple Demographics Often Identify People Uniquely (Carnegie Mellon University, Data Privacy Working Paper 3, 2000)·Unique in the shopping mall: On the reidentifiability of credit card metadata (Science 347 (6221), 2015)·Beyond Memorization: Violating Privacy via Inference with Large Language Models (ICLR 2024, 2024)·How Unique Is Your Web Browser? (Privacy Enhancing Technologies Symposium (PETS 2010), 2010)·Robust De-anonymization of Large Sparse Datasets (IEEE Symposium on Security and Privacy, 2008)
Clauses that recur across this industry, and what each one actually permits.
“to provide and improve our services”
The catch-all purpose. Analytics, profiling, personalisation, and increasingly AI training can all ride under it. When they want to do something new with your data, this sentence usually already covers it.
THE MOVE An objection draws the line: use your data to run the service, not to improve, target, or train on it.
“we do not sell your personal information”
Often technically true, and still misleading. It usually means no cash changes hands. Data can still flow to ad networks, analytics firms, and partners: on their definition, sharing is not selling.
THE MOVE Flip the do-not-sell switch where one exists. The written objection on top of it goes on your record.
“service providers, partners, and affiliates”
How data leaves the building with no name attached. Recipients are listed by what they do, never who they are. You cannot send a request to a company you cannot name, which is the point.
THE MOVE An access request can ask for the recipients by name, not just the categories. UK and EU law put that choice with you. The reply, or the silence, goes on your record.
“aggregated or de-identified information”
Stripping the name does not strip the pattern, and the pattern often still points at you. Policies grant themselves free, indefinite use of this data because in their telling it is no longer about you.
THE MOVE If a deletion comes back as 'anonymised', keep the reply. It is their claim, not a fact you can check.
“retained as long as necessary, or as required by law”
They can keep it for: legal duties, tax rules, fraud prevention, possible lawsuits, their own business reasons. None of them carries a firm end date. Deletion becomes a negotiation, not an event.
THE MOVE Which reasons apply to you, and how long each runs, is a request of its own. Their reply goes on your record.
“you grant us a licence to use your content”
A contract term, not a data setting, so a privacy request cannot undo it. The careful version ends with your account. The broad version can be passed on, never expires, and survives deletion.
THE MOVE Whether the licence ends with the account is written in their terms, not yours. Closing the account goes on your record.
“this policy does not apply to the practices of our sellers”
The platform passes your name, address, email and phone to an independent seller, then steps back from what that seller does with them. Where a platform sets a reuse rule instead of this disclaimer, that rule, not any technical limit, is all that stands between your contact record and a marketing list.
THE MOVE The platform answers for its own copy of your data; the seller answers separately for theirs. Each reply goes on your record.
“we do not sell your information as that term is generally understood, though it may be considered a sale or sharing under certain laws”
Purchase-history identifiers are routed to ad partners while the word "sale" is treated as a technicality. The clause admits the flow, because a required opt-out depends on admitting it, and denies its plain meaning in the same sentence.
THE MOVE The opt-out sits in that same paragraph; using it in writing draws the line going forward, and the reply goes on your record.
“a code derived from applying irreversible cryptography to information like your email address”
Your email is turned into a code and handed to ad platforms to match you, or people like you, off the site. The code is offered as anonymity, but a match is the whole purpose of the operation.
THE MOVE An access request covers which identifiers left and where they went. Under UK and EU law you can ask for the recipients by name, not only by category; the reply goes on your record.
Their own policy is the one that binds them. Pin it down with a request, and keep the reply. Start your record →