Proofreaders are hired to review and find mistakes in printed or digital materials. Traditionally, they were employed by newspapers and book publishers to correct initial versions of writings before they printed final copies. Now, most proofreaders work on digital formats and are hired to read blogs, news sites, social media updates, and online reviews. A Proofreader sometimes doubles as a Copy Editor, correcting grammar and spelling mistakes as they work and offering suggestions to improve the copy. They also make sure the layout of the page is readable, and that page elements do not hinder or cover any text.