The informal conversations that researchers have at scientific meetings look set to move online, if a new initiative by the US National Center for Biotechnology Information (NCBI) has its way. On 22 October, the NCBI of Bethesda, Maryland, launched the pilot phase of a programme called PubMed Commons. This will allow users to comment on published abstracts on the PubMed website, which indexes some 22 million papers.

For now, only a select group of researchers and their invited guests can use the system. But the NCBI's director David Lipman, who helped to develop the programme, says that soon any PubMed author will be allowed to comment under his or her real name.

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Lipman hopes that the fact that so many people already use PubMed will aid in the development of a discussion community, but admits that getting people to participate may be a challenge. Historically, even high-profile journal papers have not tended to attract a lot of comments, says Iain Hrynaszkiewicz, outreach director of Faculty of 1000 in London, which boasts a community of some 5,000 scientists who review published papers. And data from the Public Library of Science (PLoS), based in San Francisco, California, show that only about 10% of its journals’ approximately 90,000 papers have comments. Only a handful boast more than one comment, despite the fact that readers have downloaded more than 230 million copies of PLoS studies.

Other large journal sites, including the preprint server arXiv, have considered and rejected the idea of hosting comments. Paul Ginsparg, a physicist at Cornell University in Ithaca, New York, who founded arXiv says that they take too much work to manage and authors fear that negative comments on their papers might drive readers away. And Ginsparg doubts that allowing comments on arXiv would generate more discussion, because comment threads and blogs that link back to arXiv papers are already hosting a wealth of fruitful conversations.

Back to topic

Then there is the difficulty of making sure that comments are useful and on-topic. “If you give people a crayon and tell them to mark up the web, they’re probably going to scribble,” says Dan Whaley, the founder of, a system now in pilot tests that allows readers to annotate articles across a number of journals and news sites. One way to weed out unhelpful or off-topic remarks is to institute a system through which commenters vote on how useful a comment or its creator is. Commons' approach to the problem is to require people to comment under their own names.

Others, like microbiologist Ferric Fang of the University of Washington in Seattle, worry that without anonymity, researchers — particularly junior scientists — might shy away from criticizing papers out of worry for their careers. That is a concern of the website PubPeer, which allows users to comment on published papers anonymously. A representative of PubPeer says that most comments are from people flagging suspicious images in papers.

To make authors feel more comfortable, Commons co-founder Robert Tibshirani of Stanford University in California says that Commons will provide an option to comment as part of a collaboration rather than as an individual.

If nothing else, he adds, Commons could function as a sort of social living room for authors. “As a scientist, you spend so long on a paper and nobody reads it,” Tibshirani says. “That’s a lonely feeling; science can be a lonely job. I’d rather have ten comments of which four are negative than have none at all.”

PubMed is opening up a new avenue for scientific discussion.