arXiv, the online archive for scientific papers, received its first submission on August 14, 1991. Paul Ginsparg started it. He was then a physicist at Los Alamos National Laboratory. He wanted to automate the sharing of physics papers with a mailing list.
Many researchers now post manuscripts there before they send them to a journal. In August 2016 the journal Nature Physics wrote that manuscripts were being posted and “feedback from the community” received “before submission to a journal.” By then arXiv held more than 1.16 million papers. The Nature journals encourage authors to post their manuscripts before submission.