Is the Spread of an Idea Like an Epidemic?

I watched a TV movie last week about a bird-flu pandemic. Starts in China, whole neighborhoods closed off, food runs out, Penn Station giant hospital, millions of deaths, vaccine, baby on the way, ambiguous ending. Not bad, but not good, either. My mind kept drifting to the spread of The Shangri-La Diet.

It is like a contagious disease in the sense that it can be spread person-to-person: Person A reads the book, tries its weight-loss methods, loses weight or at least appetite, tells Person B about it, Person B reads the book, and so on. It is unlike a contagious disease in the sense that it can be spread by media — newspaper article, radio interview, etc. After spiking to #2 on after an interview on the Dennis Prager show, the rank has drifted down to about #100.

A contagious disease spreads faster and slower: faster when people are close together (subway), slower when they are apart (sleeping). But with a weight-loss idea the variations of rate of transmission are much larger. At one extreme (slow), someone tries it and then three weeks later someone else notices her weight loss and asks about its source and (if I’m lucky) decides to try it — one person “infected” in three weeks. At the other extreme (fast) is something on national TV, where hundreds of thousands of people become “infected” in minutes.

To get some idea of how the idea is spreading, I have been tracking the growth of the forums at Here are graphs of the total number of posts, topics, and members (upper graph) and the rates of their growth (lower graph). forum growth as of 5/16 forum growth rate as of 5/16

There has been little publicity since the Prager interview about two weeks ago, so the recent growth level of about 5% per day presumably reflects word of mouth/blog. The interesting fact is that the growth appears steady at about 5%.

Berkeley Public Library Watch:The Shangri-La Diet, 4 holds on 1 copy. The Omnivore’s Dilemma by Michael Pollan, 110 holds on 7 copies. Website Watch: Distinct hosts served at, latest 24-hour period: 948. One week ago: 875. Distinct hosts served is close to the number of different visitors.

Week of Long Walks

“How are you doing, after such an exciting week?” my sister asked. Well, I took several long walks — my idea of a big treat. To let the good news wash over me.

Have you heard of Blockbuster, a book by Patricia Marx and Douglas McGrath? Published in 1988? They wrote about the new-author experience in Spy: “Our book came out to whatever is the opposite of great fanfare.” They decided to hire their own publicist. One candidate told them “our book could become known only if we became known. . . . Just one day after Aeschylus died, the publicist said, his play The Suppliant Women, which had been sparsely attended and about to close, was sold out.” Another person told them, “Even if I could get you publicity for the book, which is highly, highly doubtful, what’s the difference? . . . Nothing lasts.” And nothing changes, either, at least in 18 years. Recently I asked Diane Reverand, an editor at St. Martin’s Press, what was the worst thing about being an writer. “How difficult it is to get attention for what you have done,” she replied. “So few books get any attention at all.”

Which is why, when SLD was published (April 25), I was nervous. Two factors loom large in how well a book does: (a) how many people buy the book in the beginning; and (b) how much each buyer recommends it. The first depends more on the author’s fame than anything else; the second depends on the quality of the book. These two factors roughly multiply to determine sales. Big initial audience x poor book = poor sales. Small initial audience x good book = poor sales. People in the movie industry make a similar calculation; they look at (a) size of first-weekend audience and (b) dropoff from Week 1 to Week 2.

In terms of initial exposure, SLD had two strikes against it: I wasn’t famous; and the diet was absurd (“If you had to cook up the ultimate stereotype of a wacky fad diet for use in a comedic novel or film, the Shangri-La Diet would fill the bill,” wrote For most media, the mental equation is publicize absurdity = lose credibility. On the other hand, Freakonomics authors Levitt and Dubner, my agent (Suzanne Gluck), my publisher (Putnam), my editor (Marian Lizzi), and the book’s two publicists (Stephanie Sorensen and Katie McKee) did a fantastic job of turning just about every possible lever in the book’s favor — so many levers I won’t even start to describe them.

Their efforts — and the support of Ann Hendricks, Stephen Marsh, and, yes, — have already begun to pay off. The book is #31 at — and I’m alive. On Wednesday, Dennis Prager, of the Dennis Prager show, interviewed me for an hour. Mr. Prager was extremely positive about the book. He almost never covered diet books, he said, but he was making an exception for this one. To discuss SLD was “a public service.” A public service! He himself was doing the diet, it was working for him, he was amazed how little hunger he felt. He corrected Dubner’s comment on the cover about the book helping “a few million people.” “A few billion” would be more accurate, he said. After that interview, the book soared to #2 at, where it stayed for two days. How did you do that? fellow editors asked Marian Lizzi in amazement.

Will those who buy it recommend it? Well, Kathy Sierra, co-author of Head First Java and popular blogger, didn’t buy it but did recommend it — in better-than-glowing terms. She summed up her opinion in an email to Marian, who had sent her a copy: “This book may be nothing less than a miracle.” (Ah, shucks.) It also seems to me that almost all of the forum contributors would recommend the book. And the forums are growing rapidly.

That was the good news last week.

Berkeley Public Library Watch:The Shangri-La Diet, 3 holds on 1 copy. The Omnivore’s Dilemma by Michael Pollan, 96 holds on 7 copies. Website Watch: Distinct hosts served at, latest 24-hour period: 883. One week ago: 452. Distinct hosts served is close to the number of different visitors.