The goal of open science is to improve the quality of publications and to overcome the shortcomings of the classic peer review process. Post-Publication Peer Review (PPPR) has been proposed as an alternative. It is of particular interest to study a non-anonymous PPPR platform to dive into the dynamics relative to the position of the commentators in the scientific community. This research-in-progress describes for the first time in detail the publications targeted by PPPR comments on PubMed Commons (PMC) and the commenters in order to better identify the underlying issues. From the original PMC corpus, we extracted a sample of 657 authors who wrote 4514 comments. To run a bibliometric analysis, this sample was matched with Scopus® database in order to inform the status of the commenters and of the publications. Preliminary results show that the distribution of comments over time reveals some events of intense debate. Most of the comments are rather short. The number of comments by authors follow a Pareto distribution. Commenters are scientists with a high reputation but there is no correlation between their critical activity and any bibliometrics indicators. Finally, we identified only a small fraction of retracted publications. Our results seem to reveal the heterogeneity of the profiles, reflecting a divergent interest in PPPR probably related to the researchers’ positions in the scientific field, and the respect of the Mertonian norms of the scientific ethos. Further research is currently underway to investigate these characteristics in more detail.