Unless you're an academic, you probably don't care about "impact factors", but for the world of academic journals - and the people who publish there - it's a matter of life and death (sadly.) Think of them as a kind of Google PageRank for publishing.
Anyway, the news that the trail-blazing Public Libary of Science titles have increased their impact factors is important:
The latest impact factors (for 2007) have just been released from Thomson Reuters. They are as follows:
PLoS Biology - 13.5
PLoS Medicine - 12.6
PLoS Computational Biology - 6.2
PLoS Genetics - 8.7
PLoS Pathogens - 9.3
As we and others have frequently pointed out, impact factors should be interpreted with caution and only as one of a number of measures which provide insight into a journal’s, or rather its articles’, impact. Nevertheless, the 2007 figures for PLoS Biology and PLoS Medicine are consistent with the many other indicators (e.g. submission volume, web statistics, reader and community feedback) that these journals are firmly established as top-flight open-access general interest journals in the life and health sciences respectively.
The increases in the impact factors for the discipline-based, community-run PLoS journals also tally with indicators that these journals are going from strength to strength. For example, submissions to PLoS Computational Biology, PLoS Genetics and PLoS Pathogens have almost doubled over the past year - each journal now routinely receives 80-120 submissions per month of which around 20-25 are published. The hard work and commitment of the Editors-in-Chief and the Editorial Boards (here, here and here) are setting the highest possible standards for community-run open-access journals.
This matters because many sceptics of open access would love PLoS to fail - either financially, in terms of academic influence or, ideally, both - and its continuing ascendancy in terms of impact factors is essentially a validation of the whole open access idea. And that has to be good for everyone, whether they care about academic PageRanks or not.