Open Source Software is an important economic driving force. Companies are aware of the benefits and are adopting OSS as a strategy, opening their source code. However, fostering an OSS developer community is challenging. Newcomers to OSS projects face many technical and social barriers and commonly drop out before making their first contribution. In this keynote, I will talk about how companies are opening their code, the barriers newcomers face to join OSS projects, and FLOSSCoach, a tool we developed to support newcomers first steps. About the speaker: Marco Aurélio Gerosa is an Associate Professor in the Computer Science Department at the University of São Paulo (USP), Brazil. His research lies in the intersection between Software Engineering and Social Computing, focusing on the fields of empirical software engineering, mining software repositories, software evolution, and social dimensions of software development. He has published more than 150 peer-reviewed papers. He served as Program Chair at IEEE ICGSE 2016 and PC member in several conferences, such as ACM CSCW, SANER, MSR, etc. In addition to his research, he also coordinates award-winning open source projects.