More biomedical journals are expected to join PubMed Central as a result of a substantial loosening of the conditions for participation. The National Library of Medicine's free web based repository of peer reviewed research has been struggling to sign up journals since it went live 15 months ago (http://pubmedcentral.nih.govhttp://pubmedcentral.nih.gov/).
Previously, publishers had to agree to their peer reviewed articles appearing in full on PubMed Central, giving users little incentive to visit publishers' own sites or renew their journal subscriptions. Now PubMed Central is prepared to link out to publishers' sites for the full text.
The conditions are that publishers must make this content freely available from their own sites within a year, but preferably within six months, of publication. If publishers stop making content freely available from their sites PubMed Central will provide it instead.
Publishers will still need to submit the full text of articles to PubMed Central to allow more sophisticated indexing and searching than is possible using abstracts alone. Although these new functions are yet to materialise, it was their prospect that led PubMed Central's architects originally to propose a central rather than a distributed repository of articles. For publishers, an important benefit of submitting full text articles is the creation and preservation of a digital archive of their content by the National Library of Medicine.
Meanwhile, the Public Library of Science's open letter continues to gain support, with some 13000 signatories from 126 countries as we went to press (http://www.publiclibraryofscience.orgwww.publiclibraryofscience.org). Written by some of PubMed Central's proponents, the library pledges that from this September, it "will publish in, edit or review for, and personally subscribe to, only those scholarly and scientific journals that have agreed to grant unrestricted free distribution rights to any and all original research reports that have been published, through PubMed Central and similar online public resources, within six months of their initial publication date."
Still reeling from the original proposals of PubMed Central, publishers are now facing a boycott from the communities that they both serve and profit from. All sides of the argument are likely to be touched on in a debate on electronic initiatives intended to bring free access to the primary scientific literature, which began on Nature 's website this week (http://www.nature.comwww.nature.com).