Following the Breadcrumbs on the Data-Sharing Trail

WOULD you like to donate to the Obama campaign? Sign up for a college course? Or maybe subscribe to Architectural Digest?

If you have ever felt inundated by such solicitations, by e-mail or by snail mail, you may have wondered what you did to deserve it.

I did.

I wondered how all those campaigns, companies and institutions got my number. And how much money data brokers behind the scenes might make by flipping my name and address.

Turns out there’s no easy way for consumers in the United States to track the data dealers who profile our spending, Web browsing and social media habits, the better to sell us stuff. Although the Federal Trade Commission issued a consumer privacy report last month urging companies that collect and share customer information to give people more notification and control over the proliferation of their personal details, the recommendations don’t have the force of binding regulations.

So, without a right to compel vendors to show me where my data goes, I decided to do some profiling of my own.

I subscribed to a half-dozen print magazines last year, signing up for each with a different typo in my name or variation in my address. Then I collected the direct mail that resulted, tracking the solicitations back to the publishers who had shared my erroneous contact information.

Admittedly, it was unscientific. But I figured this little off-line experiment might provide insight into an even more opaque world — online behavioral targeting — where ad networks deliver tailored marketing pitches to people based on their location, search queries, online purchases and the like.

Here are the results:

Natawsha, the name under which I had subscribed to Wired and The New Yorker, got hit up for a donation to Literacy Partners, a tutoring company in Manhattan, and received a bulletin from the New-York Historical Society.

Nafasha, who signed up for Fast Company, received solicitations from Forbes. The mangled address I had submitted to Foreign Policy received a cascade of mail from, among others, the World Monuments Fund, Barron’s and the Kiplinger Letter. And a subscription to The New York Review of Books led to solicitations from the Central Park Conservancy, the New York Public Library and The New York Times — and, on behalf of President Obama’s 2012 campaign, an appeal from Michelle Obama.

“It is revenue-producing for a publisher to collect subscribers’ information and sell it,” said Paul Stephens, the director of policy and advocacy at the Privacy Rights Clearinghouse, a consumer group in San Diego. “It’s just information that is very valuable to advertisers who want to target individuals based on their interests.”

INDEED, the Direct Marketing Association, a trade group, has estimated that spending on direct marketing in the United States reached $163 billion in 2011.

Still, a report earlier this year from the White House, laying out a privacy bill of rights for consumers, implicates the decades-old practice of list-sharing, among others. The report says consumers have a right to expect that companies will collect, use and share information in ways consistent with the context in which people provided it.

In other words, if you subscribe to a magazine, you might reasonably expect to receive offers from magazines owned by the same publishing house, said Nancy J. King, a privacy law expert who is an associate professor at Oregon State University’s College of Business.

“But you probably would not have expected a magazine to share your information with a political campaign” that has inferred your political preferences from your choice of periodicals, Professor King said.

Of course, publishers are hardly the only businesses sharing and selling consumer information. In the United States, with the exception of specific sectors like credit and health care, companies are free to use their customers’ data as they deem appropriate. That means every time a person buys a car or a house, takes a trip or stays in a hotel, signs up for a catalog or shops online or in a mall, his or her name might end up on a list shared with other marketers. That can happen directly, or through middlemen known as list brokers and data brokers.

The ultimate purpose of all this sharing and profiling is to personalize marketing, using analytics to predict the offers most likely to interest consumers based on their past behavior, says Linda A. Woolley, the executive vice president of Washington operations at the Direct Marketing Association.

“Sometimes the analytics are right; sometimes they are wrong,” Ms. Woolley said. “The industry exists to try to perfect those guesses.”

For those who’d rather not receive such offers, she said, the trade group offers a dedicated Web site, dmachoice.org, where people can opt out of getting all kinds of direct mail or specific categories of it, like credit card offers.

But Christopher Olsen, the assistant director of privacy and identity protection in the Federal Trade Commission’s bureau of consumer protection, said companies ought to notify their customers if they plan to share information about them with third parties — rather than simply permitting people to opt out after the fact. Indeed, the agency’s recent report calls on industry to be more transparent with consumers.

“If your name is flying around the ether because you have subscribed to a magazine,” Mr. Olsen said, “you ought to understand who has got that information and whether you have a choice about its onward distribution.”

ALTHOUGH all of the magazines contacted for this article said their subscribers could opt out, some publishers took a more active approach than others to notifying readers of their practices.

Natalie Raabe, a spokeswoman for The Atlantic, for example, said the magazine occasionally allows companies it has screened to contact subscribers about products or services that may be of interest. But the magazine does not share subscriber addresses directly with these companies, she said; it uses a third party to administer the process.

A spokeswoman for Condé Nast, publisher of The New Yorker, said it adhered to industry best practices and offered subscribers multiple ways to opt out.

Diane R. Seltzer, list manager at The New York Review of Books, vets all proposals from companies that want to market to subscribers to ensure the offers are appropriate. Those making the cut are charged a rental fee of $105 per 1,000 names for one-time use, she said. The publication runs an ad in every issue, she added, notifying subscribers of this practice and explaining how to opt out.

“We are very proactive in trying to keep subscribers happy,” she said.

In light of the new federal privacy reports, however, at least one publisher said it might halt, or at least further limit, the selling of its subscriber list.

“I think media companies are going to have to tackle this issue,” said David Rothkopf, the new chief executive of Foreign Policy. Two months into the job, he said, he had hired a new circulation director and intended to review his magazines’ list-sharing policy: “I think there are people out there who don’t want to be part of some giant circulating mailing list.”

E-mail: slipstream@nytimes.com.