This firstly explains briefly what peer review is. Then it talks about facilities that have become available recently i.e. PubMed Commons, Pubpeer.com, Publons.com and (briefly) Libre. Unfortunately for PubMed Commons and Pubpeer.com, one needs to be listed in PubMed to make submissions. Soon anyone will be able to read the PubMed Commons. The easiest way for many here to get in PubMed is to write a (published) letter to the editor.