Nature's roundup of the papers and issues gaining traction on social media.

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Here's a novel approach for getting an article noticed: put 'Kardashian' in the title. A paper that compared Twitter-using researchers to the celebrity Kim Kardashian incited a backlash on social media. Online observers also had some choice words for a paper that purported to chart the spread of culture over time.

Neil Hall, a genomics researcher at the University of Liverpool, UK, introduced a metric called the Kardashian Index, or K value. This is calculated by dividing a researcher's number of Twitter followers by the number of scientific citations he or she has. The K value supposedly identifies scientists whose visibility exceeds their contributions — somewhat like a certain socialite, Hall suggests. The article was intended as satire, but not everyone was amused. “This paper suggests only highly cited scientists deserve a large Twitter following, & everyone else should shut up,” tweeted Katie Mack, an astrophysicist at the University of Melbourne in Australia.

In the paper, Hall writes that the Kardashian Index could be used to identify researchers who have “an overblown public profile so that we can adjust our expectations of them accordingly”. The response was immediate. Some liked the joke: “I have a high K (20) and I found it amusing,” tweeted Ted Hart, an ecologist at the National Ecological Observatory Network in Boulder, Colorado. But Mack, who has more than 12,000 followers, said in a follow-up interview that the paper was “insulting” to people who, like her, use Twitter to connect with the public and to show the human side of scientists. She has also heard from young women over the years who say that her tweets and blog posts encouraged them to pursue scientific careers. “We could all quit Twitter and get back to writing our papers,” she said, “but would society really be better off? I don't think so.”

Kate Clancy, an anthropologist at the University of Illinois at Urban-Champaign, argues on her blog that Hall's article mocks scientists who tend to have fewer publications and be “younger, less white, and less male.” “Hall punches at people with less power,” she writes, “That makes it not funny.” Reached for further comment, Clancy said that it's unfair for a scientist working in genomics to make light of the citation counts of researchers in fields such as anthropology, in which journals tend to have lower impact factors than biomedical journals. She added that “there's a lot of sexism” behind Hall's choice of Kim Kardashian as the standard-bearer for unwarranted fame.

Neuroscientist Micah Allen at University College London defended his own social-media activities on his blog. “It may not seem like it now — but in time it will be clear that what we do is just as much a part of the scientific process as those lofty Nature papers,” he wrote. “Wear your Kardashian index with pride.”

Hall was on holiday and couldn't be reached for comment at the time of publication. He did, however, briefly weigh in on Twitter to say that he meant to poke fun at the use and misuse of metrics to measure scientific contributions: “The point, clearly not communicated well enough ..., is metrics are daft. And 'popularity' is not a good measure either.” In another tweet, Hall wrote: “Clearly I'm glad that people are discussing the k index. It is a joke! I don't have anything against students with few publications.”

Hall, N. Genome Biol. 15, 424 (2014)

A different sort of controversy arose from a paper that attempted to chart the historical movement of culture through the birth and death locations of more than 150,000 “notable” people across 2,000 years. The report, and the visually arresting online video that goes with it, graphically depicts the dispersal of early Romans and the emergence of other cultural centres, such as London and Paris. The study also identifies “death attractors” as places where death records significantly outnumbered birth records, a list that includes Washington DC, Los Angeles and Auschwitz.

Some researchers took to social media to express admiration for the sheer scope of the project. Terry Hébert, a pharmacologist at McGill University in Canada, tweeted that it was “big data applied to human history”. But others thought the analysis took a too-narrow view of culture that left out large parts of the world, a limitation that the authors noted in their paper. Maximilian Mayer, a political scientist at the University of Bonn, Germany, tweeted: “A typical example of garbage in, garbage out. Striking, these racial stereotypes and a top-down Euro-centric 'history'.” However, Tatsuya Amano, a conservation biologist at the University of Cambridge, UK, tweeted: “Great visualisation of intellectual mobility. Birth-death distance is not that different between the 14th and 21st C.”

Schich, M. et al. Science 345, 558–562 (2014)