Glossary
Browser autofill
Browser autofill is the feature that stores what you type into web forms - email address, name, postal address, sometimes card details - and offers it back as a suggestion whenever it recognises a similar field. It is separate from saved passwords, and on most browsers it is switched on by default.
GlossaryPrivacyBillingSafety
Where you see it
It appears as a small dropdown under a sign-up, login or checkout field the moment you click into it, and again on unrelated sites, because a stored address or card entry is offered wherever the form looks like a match.
Why it matters
The exposure is rarely on the adult site itself - it is the suggestion surfacing later, in front of someone else using the same browser profile. Stored card details also turn a token purchase into a single tap, which is worth thinking about if you are trying to hold a budget. Autofill entries are cleared separately from history, so wiping history can leave them intact.