BOB GARFIELD: Have you ever felt like the Web you’re watching is watching you back, you know, like when an ad pops up on your screen for a tee-shirt of your favorite band, which you listed as your favorite on your Facebook page, that kind of marketing, called behavioral advertising, where marketers track where you go and what you do on the Web in order to sell you things. It’s pretty much the norm these days. And marketers have always said that people don't mind because the ads are for the stuff they might actually want. But a study that came out last month done by the University of Pennsylvania and the University of California at Berkeley found that nearly two-thirds of people are against tailored ads. Professor Joseph Turow, lead author of the study, says the implications strike at the heart of the digital privacy issue.

JOSEPH TUROW: What the public is concerned about is that the pictures that advertisers draw about you are becoming more and more vivid, and whether or not they have pictures that you would agree with is a really big question. So I think the issue here is how much do people know about what’s going on, and do they have any control over it? So, for example, if you get an ad, say, from NewYorkTimes.com and it’s tailored to you, it would be great if there were a way that you could know, a) that’s it tailored for you, b) where did they get those data from, c) how does it fit into a larger picture of you that that advertiser or that periodical has? And can you do anything about it?

BOB GARFIELD: Now, you had warned that if nothing is done on this issue that it could really spiral out of control. What’s the nightmare scenario that you see say, a decade from now?

JOSEPH TUROW: Well, the scenario I see, whether we call it a nightmare or not, is the digitization of all media and their interconnection. The kinds of activities that are being tested in the Internet are going to be applied quite directly to television, to stores, to other areas. And they're going to be interconnected. We're setting up a situation where people will feel that their reputations may affect even what 60 Minutes they see. It’s quite possible, for example, to imagine a 60 Minutes program that I get that’s very different than the 60 Minutes program you get because of the socio-demographics and psychographics that they've decided about you versus me.

BOB GARFIELD: Some of that went on even in the analog world, where there were zoned editions of newspapers based on your geographical interests, but the digital world enables you to slice and dice that a batrillion ways, that maybe now people are just beginning to realize it?

JOSEPH TUROW: I think that’s true, and I think that there are contradictions here, and complexities. There’s actually a lot more data that supermarkets have about you than most websites. People, studies have shown, including ours, are much more concerned about the online world than the offline world, when there’s a lot more data flow about you going on in the offline world [LAUGHS] than in the online world.

BOB GARFIELD: Which you've absolutely surrendered, you know, in exchange for nine cents off of a can of clam chowder. You’re using a discount card and they are tracking all of your Preparation H purchases, and every-thing else.

JOSEPH TUROW: And right now most people don't see that, because supermarkets haven't quite figured out what to do with all those data. But when they start doing that, and when the mobile phone gets connected to the supermarket activity and when all of that gets connected to your online data, that’s when that confluence of forces, that perfect storm, might erupt.

BOB GARFIELD: I want to ask you about privacy, in general, because all of these issues seem to boil down to people’s sense of the right of privacy being absolute. But increasingly in the [LAUGHS] 21st century, privacy is kind of a commodity, isn't it, that travelers exchange for security and then celebrities exchange for, for celebrity? Do you think that one of the outcomes of this, ten years from now, is that people will be more likely to understand that their privacy is a commodity that they can trade for something of value?

JOSEPH TUROW: I think some people understand that now, but it’s really an ethical societal question that we have to deal with. Basically the question is, is your data, information about you, is it body or barter? Is it something that belongs to you that you want to keep it and husband to yourself, or is it something you’re willing to trade? And also, who owns that information? The point is, I'm not against behavioral targeting. I'm against behavioral targeting that takes place in a situation where people have no knowledge and no control.

BOB GARFIELD: Well Joe, thank you very much.

JOSEPH TUROW: Thank you. I appreciate it.

BOB GARFIELD: Professor Joseph Turow is the lead author of the study and professor of communication at the Annenberg School for Communications at the University of Pennsylvania.