Google uses targeted ads and so does Facebook. But it turns out that Amazon’s treasure trove of 152 million customers’ data is at the top of the digital heap. “Since last year, the world’s largest online retailer has been packaging information on what it knows about consumers so that some marketers can use it to make split-second decisions about where to buy ads online and how much to pay for them,” reports Technology Review.

This process occurs on automated, real-time ad exchanges that sell ad impressions as people load Web pages.

Amazon has an in-house platform for targeting ads to people who’ve visited and left Amazon’s sites, “making it likely that the company will open up these advertising services more widely over the next year,” suggests Technology Review.

Thus far, at least in comparison to Google and Facebook, advertising has been a small part of its business, notes the article. “It brought in about $500 million of Amazon’s $48 billion in revenue in 2011, Baird & Co. senior research analyst Colin Sebastian estimates.”

In what is most likely the future typical scenario, “Amazon would create target audiences, such as people who recently purchased digital cameras. A marketer selling digital camera accessories could then use Amazon’s technology to bid for the ability to show ads to a person in that category.”