We passed a landmark today: As of 16.50h GMT, our users have uploaded one million articles to their Mendeley accounts! Including the cited references which Mendeley also extracts from research papers, we now have over 14 million metadata sets in our database. Even we were surprised by the speed in which this has happened!

For the record, the millionth article added to our database was “The somatic marker hypothesis: A critical evaluation“ by Dunn et al. (2006) in Neuroscience and Biobehavioral Reviews – as luck would have it, that’s a topic related to my personal research on the role of emotions in decision making! The closest publication by one of our users, Joaquin Rivera, was added at 17.01h – a maths paper titled “On the exact multiplicity of solutions for boundary-value problems via computing the direction of bifurcations”, available for download on Joaquin’s Mendeley profile.

90% of these one million articles have been uploaded since January 2009, and our database is currently doubling in size every 6 weeks. For comparison, venerable PubMed – the largest database of biomedical literature – contains 18,813,527 records as of today. Assuming we managed to keep up our growth, we could surpass the size of the PubMed database within the next 6 months!

Roughly 43% of the papers in our database are in the biological and medical sciences (even though only about 27% of users are working in these academic disciplines). Computer and information science comes in second with roughly 11% of all papers, followed by engineering with 7%, and chemistry, physics, psychology and other social sciences with 4-5% each.

As we’ve said before on this blog and elsewhere (e.g. see my talk at the Plugg Conference), we’re not hoarding all that data just because we can, no Sir! Our vision is to create the largest open, interdisciplinary and ontological database of research – as crazy as that sounds, remember that Last.fm (whose former chairman and COO are our co-founders and investors) pulled it off in the space of music within just three years, using the same user data-aggregation model that Mendeley is built on.

We’ve already begun to report real-time “usage-based” research trends – a nice discussion of Mendeley statistics showing the most-read journal in the biological sciences can be found here (we’ll be writing more about this soon!). Analogous to Last.fm, we will provide APIs to let others mash up the research statistics we’re generating. Moreover, our database will be the basis for our upcoming collaborative filtering recommendation engine: Based on the articles in your Mendeley library, we will be able to tell you about articles you don’t know yet, but which have been read and recommended by researchers with similar interests. You can read more about these plans in our recent IEEE e-Science paper.

A big thank you to our wonderful users who have been helping us improve Mendeley with their constant feedback. After celebrating the millionth article upload tonight, we’ll get back to work on our next two releases, packed full with exciting new features!