Dr. Susannah B. F. Paletz is a Research Scientist and the Technical Director for Organizational Behavior and Performance at the University of Maryland Center for Advanced Study of Language. She received her Ph.D. in social/personality psychology at the University of California, Berkeley (2003). She previously worked for NASA Ames Research Center as a research psychologist and at the University of Pittsburgh as a postdoctoral and research associate. In addition to studying issues of teamwork, innovation, and culture, she applies psychological concepts to applied problems within aerospace, science and technology, and defense domains. She has authored over 25 peer-reviewed articles and book chapters, and over 30 additional technical reports.Ms. Brooke E. Auxier is a PhD candidate (expected graduation, 2019) in the Philip Merrill College of Journalism at the University of Maryland, College Park. She is also the director of social journalism andaudience engagement for Merrill College’s non-profit news organization, Capital News Service, and an instructor in the School of Information Studies at Maryland. She has worked social media strategy and data analytics with companies like Apple, Marriott, and Discovery Communications. As a researcher, she is focused on how users interact and engage with information in social media environments. Her dissertation work focused on examining how users determine the trustworthiness and credibility of information- and news-sharers in social media spaces.Dr. Ewa M. Golonka holds a PhD in Russian Linguistics and Second Language Acquisition from Bryn Mawr College (2000). She is currently an Associate Research Scientist at the University of Maryland Center for Advanced Study of Language (CASL), where for the past fourteen years she has worked on over a dozen multi-disciplinary research projects. She has been a Principal Investigator (PI) or co-PI on four Departmentof Defense-funded interdisciplinary projects ($4.5 million total). She was a key scientist on three Russian/Ukrainian social media projects at CASL, where she led the analyses of linguistic variation in Russian and Ukrainian social media corpora. Dr. Golonka has authored 14 peer-reviewed articles and book chapters and over 50 technical reports, and she is the first author on a journal article that is most read and most cited in the Computer Assisted Language Learning Journal (Impact Factor 2.12). In 2018, she was included in #100WomenInScience, a list of 100 most-downloaded articles by women from Taylor & Francis journals in the last five years.

• Chapter1. Introduction.- Chapter2. Sources of Messages.- Chapter3. Reactions to the Message and Messenger.- Chapter4. Motivation to Share.- Chapter5. Context and Match Between Context and Model Components.- Chapter6. Non-Genuine Actors.- Chapter7. Ability to Share.- Chapter8. Conclusion and Discussion.