PubPeer is a website that allows users to discuss and review scientific research. The site is one of many allowing academics to engage in post-publication peer review. It has served as a whistleblowing platform, in that it highlighted shortcomings in several high-profile papers, in some cases leading to retractions and to accusations of scientific fraud, as noted by Retraction Watch. Contrary to most platforms, it allows anonymous post-publication commenting, a controversial feature which is the main factor for its success. Consequently, accusations of libel have been levelled at some of PubPeer's users; correspondingly PubPeer comments are required to use only facts that can be publicly verified.