The results are surprising — well, to me, anyway. I would have hypothesized that there are two basic strategies for making the most-e-mailed list. One, which I’ve happily employed, is to write anything about sex. The other, which I’m still working on, is to write an article headlined: “How Your Pet’s Diet Threatens Your Marriage, and Why It’s Bush’s Fault.”…

Perhaps most of all, readers wanted to share articles that inspired awe, an emotion that the researchers investigated after noticing how many science articles made the list. In general, they found, 20 percent of articles that appeared on the Times home page made the list, but the rate rose to 30 percent for science articles, including ones with headlines like “The Promise and Power of RNA.” (I swear, the science staff did nothing to instigate this study, but we definitely don’t mind publicizing the results.)

“Science kept doing better than we expected,” said Dr. Berger, a social psychologist and a professor of marketing at Penn’s Wharton School. “We anticipated that people would share articles with practical information about health or gadgets, and they did, but they also sent articles about paleontology and cosmology. You’d see articles shooting up the list that were about the optics of deer vision.”