Yesterday, we told you about a Home Depot customer who was put off by an e-mail from the retailer asking him to review a product he’d purchased in-store. He assumed the store must have linked the credit he used at the store with a purchase he’d made on HomeDepot.com a year earlier. And he’s just about right.

In response to our request for an explanation of how this could have happened, a rep for Home Depot tells Consumerist:

“Our policy is to send product review emails like this only to customers who opt in to receive email regarding products and promotions – and those emails may include product reviews. It’s our way of making the content for customers more relevant and meaningful to their purchasing interests, and another way for us to get honest feedback about the products we sell. We gladly and promptly remove anyone from the system who asks, and we’ve only had a handful of those requests. It’s also very important to note that the IT systems that make this possible do not track credit card numbers. They do, however, recognize a credit card through a unique identifier that matches up with purchases online or in the store. Again, we’ll remove anyone from the list if they’re not comfortable with that, but it’s very well intended to avoid sending customers emails that have nothing to do with their interests.”

So it’s not specifically credit card numbers, but “unique identifiers” that are somehow tied to the credit card info that Home Depot uses in order to stalk customers.

The statement is lacking in two very big ways — A: It doesn’t explain how customers can opt out. B: It doesn’t say that Home Depot only uses this information for marketing e-mails. It says that the e-mails are only intended for opt-in customers, but that doesn’t mean the retailer isn’t using this information for its own research purposes anyway. It seems to us that it would be quite valuable to know what your customers are buying online versus in-store, and there may be no way to opt out of that.

We’ve put these questions to Home Depot and will update if we get a response.

UPDATE: Home Depot has responded to our questions about these two remaining issues.

Regarding the collection of data, the retailer says it does keep the tracking info, regardless of whether or not you opt out of the e-mails.

“We have the data but don’t send any emails unless the customer opts in,” explains the company rep.

As for opting-out (which, to make clear, only gets you out of the e-mails but still allows Home Depot to track your online and in-store purchases), the rep says there is a link at the bottom of each e-mail.

Want more consumer news? Visit our parent organization, Consumer Reports, for the latest on scams, recalls, and other consumer issues.