As New Yorkers scrolled, surfed and searched their way to digital deals on Black Friday, they had certain unique protections.

This month, New York became the first state to enact a law targeting a practice, typically called personalized pricing or surveillance pricing, in which retailers use artificial intelligence and customers’ personal data to set prices online.

The law aims to prevent retailers from ripping off unwitting customers by abusing their data: jacking up the price of jeans for a shopper with a history of buying expensive pants, say, or lifting hotel prices for a traveler who already splurged on airline tickets.

Enacted through the state budget, the law requires retailers that use personalized pricing to post the following disclosure: “THIS PRICE WAS SET BY AN ALGORITHM USING YOUR PERSONAL DATA.”

The law attracted criticism and litigation from the start. Some business interests say it is far too broad and will cause confusion. And some consumers’ rights groups, who sought an outright ban of the practice, which is also called algorithmic pricing, worry the law is too narrow to meaningfully protect all shoppers from price-gouging.

But just about everyone seems to agree that the law, which last month survived a challenge in federal court, is a significant step in the nationwide push to regulate how businesses use their customers’ data.

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