Advertising drives the modern digital economy. Whether it’s reading news sites like this one or perusing your social media feeds, advertising is the single most important industry that came out of the development of the web. Yet, for all the tens of billions of dollars poured into online advertising just in the United States alone, how much does that money actually do its job of changing the minds of consumers?

Tim Hwang has a contrarian stance: it doesn’t. In his new book published as a collaboration between Logic Magazine and the famed publisher Farrar, Straus and Giroux, he argues in “Subprime Attention Crisis” that the entire web is staring into an abyss of its own making. Advertising is overvalued due to the opaqueness of the market, and few actors are willing to point out that the advertising emperor has no clothes. Much like the subprime mortgage crisis, once people come to realize the true value of digital ads, the market could crater. I found the book provocative, and I wanted to chat further with Hwang about his thoughts on the market.

Hwang formerly worked at Google on policy and has developed many, many projects across a whole swath of tech-oriented policy issues. He’s currently a research fellow at Georgetown’s Center for Security and Emerging Technology.

This interview has been condensed and edited for clarity.

TechCrunch: Let’s dive straight into the book. How did you get started on this topic of the “subprime attention economy”?

Tim Hwang: There were two incidents where I was like, something is going on here. I was having conversations with a couple of friends who are product managers at Facebook, and I remember making the argument that that there’s a lot of evidence to suggest that this whole adtech thing is maybe just mostly garbage. The most interesting thing that they said was, “Oh, like, advertising works but we can’t really tell you how.” That’s like talking to someone from the national security establishment and they’re like, “Oh yeah, we can stop terrorists but, like, we can’t tell you exactly how that goes down.”

I think one thing that got me really interested in it was how opaque a lot of these things are. The companies make claims that data-driven programmatic advertising really is as effective as it is but then they’re kind of strangely hesitant to show evidence of that.

Second, I was doing research with a lot of people who I think you’d rightly call sort of tech critics — strong critics of the power that these platforms have. I think one of the most interesting things is that even among the strongest critics of tech, I think a lot of them have just bought this claim that advertising and particularly data-driven advertising is as powerful as industry says it is.

It’s a kind of strange situation. Tech optimists and tech pessimists don’t agree on a whole lot, but they do seem to agree on the idea that this sort of advertising works. That was what I wanted to explore in the book.

Why don’t we talk a bit about the thesis?

The thesis of the book is really quite simple, which is you look around and basically our modern experience of the web is almost entirely shaped by advertising. The way social media is constructed, for example, is largely as a platform for delivering ads. Engagement with content is really good for creating profiles and it’s really good for delivering ads. It really has been the thing that has powered the current generation of companies in the space.

As you sort of look closer though, it really starts to resemble the market bubbles that we know of and have seen in other places. So explicitly, the metaphor of the book is the subprime mortgage crisis. I think the idea though is that you have this market that is highly opaque, there’s a lot of evidence to suggest that the value of ads is misidentified, and you have a lot of people interested in boosting it even in spite of all that.