By David Rapp

Citation metrics have long been the accepted measure of paper and journal importance in academia. Services that combine reference management with social-networking functionality, however, may provide an alternative way to measure that importance—by letting users decide. The popularity of such services could eventually change how academic publishers promote their catalogs.

Several services have combined reference management with social-networking aspects, such as ResearchGATE, Academia.edu, CiteULike, Connotea, and BibSonomy. One popular service is Mendeley, which has some 500,000 users. Via a desktop client, users can directly upload PDFs, from which Mendeley's software automatically extracts metadata; it then uses databases such as PubMed, arXiv and CrossRef to try to match the metadata with existing papers and get accurate bibliographic information, which can then be shared with others online.

Altogether, more than 40 million documents have been uploaded via Mendeley alone, from top schools on down the ranks, including many institutions worldwide. The tool has become so popular that London, England-based Mendeley recently opened a New York office.

Mendeley tracks the most-listed papers by its users in various fields. Because it collects user data, it can also provide demographic information with these results: such as what type of researcher is most often listing a particular paper. As Mendeley's community grows, the pool of data is becoming more robust, and a new web-based service, ReaderMeter, is using this data in an attempt to gauge impact.

Opening up data
Recently Mendeley opened up its application programming interface (API) so that outside developers could create new applications using Mendeley data. Dario Taraborelli, a researcher at the University of Surrey in the UK, officially launched ReaderMeter last month, which aims to measure the impact of a particular authors by tracking how often their papers are listed by Mendeley's users. (According to the ReaderMeter FAQ, Taraborelli plans to eventually incorporate data from other sites with open APIs, including CiteULike and BibSonomy.)

The open Mendeley API has been used by a number of organizations, Mendeley president and cofounder Jan Reichelt told LJ, such as Biostor.org, which is using the Mendeley API to provide authenticated access to their interface to the Biodiversity Heritage Library. The Annals of Botany journal, which is published by the Oxford University Press, is using it to find and display bibliographies that feature its content.

The social publisher
A few services already have close ties to publishers; for example, CiteULike is sponsored by Springer, and Connotea was created by Nature Publishing Group. As Mendeley's popularity grows, other publishers are considering it as a way to promote their content.

Several have expressed interest in having Mendeley index their holdings, Reichelt said, so that Mendeley can link directly to the original sources of papers. (Mendeley currently provides links to full text at the publisher's websites, when it is available.) Reichelt said that Mendeley is also planning to implement OpenURLs, which has attracted interest from librarians.

Right now, full-text papers are not available natively in Mendeley's research catalog, "but some researchers have made documents and pre-prints available as a link from their profile as permitted by their agreement with individual publishers," Reichelt told LJ. In addition, Mendeley has had plenty of documents uploaded that aren't scholarly papers or articles, including "case reports, literature reviews, book chapters, patents, theses, and anything else that can be found in PDF form that a researcher may wish to cite," said Reichelt.

It remains to be seen if crowdsourcing reference management will have an impact on academia as a whole. But, so far, it seems to have researchers and publishers thinking in new ways.