Publishing content, reports, books, etc is one-thing. Making sure you have the punctuation, grammar and spelling right is another battle. It is so easy to miss it and to publish content which looks untidy, unprofessional, rough, because of those small mistakes. Since high school, making sure grammar, syntax and spelling were right, has always been critical to me. In the professional world, since more than ten years, I exercised proofreading both in my corporate and freelance career. I have always been trusted by colleagues and/or customers for my exceptional proofreading.
References: Société Générale, Vodafone, Path, Diageo, etc.