Everything Is Obvious_ _Once You Know the Answer - Duncan J. Watts [147]
7. See Howe (2008, 2006) for a general discussion of crowdsourcing. See Rice (2010) for examples of recent trends in online journalism.
8. See Clifford (2010) for more details on Bravo, and Wortman (2010) for more details on Cheezburger Network. See http://bit.ly/9EAbjR for an interview with Jonah Peretti about contagious media and BuzzFeed, which he founded.
9. See http://blog.doloreslabs.com for many innovative uses of crowd sourcing.
10. See Paolacci et al (2010) for details of turker demographics and motivations. See Kittur et al. (2008) and Snow et al. (2008) for studies of Mechanical Turk reliability. And see Sheng, Provost, and Ipeirotis (2008) for a method for improving turker reliability.
11. See Polgreen et al. (2008) and Ginsberg et al. (2008) for details of the influenza studies. Recently, the CDC has reduced its reporting delay for influenza caseloads (Mearian 2009), somewhat undermining the time advantages of search-based surveillance.
12. The Facebook happiness index is available at http://apps.facebook.com/usa-gnh. See also Kramer (2010) for more details. A similar approach has been used to extract happiness indices from song lyrics and blog postings (Dodds and Danforth 2009) as well as Twitter updates (Bollen et al. 2009).
13. See http://yearinreview.yahoo.com/2009 for a compilation of most popular searches in 2009. Facebook has a similar service based on status updates, as does Twitter. As some commenters have noted (http://www.collisiondetection.net/mt/archives/2010/01/the_problem_wit.php), these lists often produce rather banal results, and so possibly would be more interesting or useful if constrained to more specific subpopulations of interest to particular individuals—like his or her friends, for example. Fortunately, modifications like this are relatively easy to implement; thus the fact that topics of highest average interest are unsurprising or banal does not imply that the capability to reflect collective interest is itself uninteresting.
14. See Choi and Varian (2008) for more examples of “predicting the present” using search trends.
15. See Goel et al. (2010, Lahaie, Hofman) for details of using web search to make predictions.
16. Steve Hasker and I wrote about this approach to planning in marketing a few years ago in the Harvard Business Review (Watts and Hasker 2006).
17. The relationship between sales and advertising is in fact a textbook example of what economists call the endogeneity problem (Berndt 1991).
18. In fact, there was a time when controlled experiments of this kind enjoyed a brief burst of enthusiasm among advertisers, and some marketers, especially in the direct-mail world, still run them. In particular, Leonard Lodish and colleagues conducted a series of advertising experiments, mostly in the early 1990s using split cable TV (Abraham and Lodish 1990; Lodish et al. 1995a; Lodish et al. 1995b; and Hu et al. 2007). Also see Bertrand et al. (2010) for an example of a direct-mail advertising experiment. Curiously, however, the practice of routinely including control groups in advertising campaigns, for TV, word-of-mouth, and even brand advertising, never caught on, and these days it is mostly overlooked in favor of statistical models, often called “marketing mix models” (http://en.wikipedia.org/wiki/Marketing_mix_modeling).
19. See, for example, a recent Harvard Business School article by the president and CEO of comScore (Abraham 2008). Curiously, the author was one of Lodish’s colleagues who worked on the split-cable TV experiments.
20. User anonymity was maintained throughout the experiment by using a third-party service to match Yahoo! and retailer IDs without disclosing individual identities to the researchers. See Lewis and Reiley (2009) for details.
21. More effective advertising may even be better for the rest of us. If you only saw ads when there was a chance you might be persuaded by them, you’d probably see many fewer ads, and possibly