It’s a closed pilot at the moment. Details below.
What is PubMed Commons?
NCBI has released PubMed Commons, currently in pilot phase, which is a new system that enables researchers to share their opinions about scientific publications indexed in the PubMed database. This is intended to be a forum for open and constructive criticism and discussion of scientific issues.
From the NCBI Blog:
We are piloting a beta version to gain perspective from the experiences of the community generally as well as from community discussions and feedback. Current participants will also be able to invite more people into PubMed Commons. We look forward to continuing to improve the service before releasing it more broadly.
During the closed pilot phase, several organizations have provided us lists of approved e-mail addresses of PubMed authors, and if you are on one of these lists, you can request an invitation to join PubMed Commons. You can find out if you are on one of these lists at the Join PubMed Commons page. We also offer an option for academic and research institutions to add to these lists.
Direct to PubMed Commons
Direct to: PubMed Commons FAQ
Direct to: PubMed Commons on Twitter