This research (1) gathered data from a sample of employees on their social media practices and the social media policies of their employers and (2) investigated how blogging and other social media added to a model of organizational climate that promotes (a) knowledge sharing and cooperation, and (b) trust in peers and management. The research integrated theories of social capital, trust, organizational climate, and knowledge sharing to test claims that social media add value to firms in social dimensions above and beyond knowledge sharing. Modest but statistically significant associations of social media use, trustworthiness of employees and management, cooperation, and knowledge sharing were found. A hypothesis that social media use would fit a specific model incorporating organizational climate and knowledge sharing and combination had mixed evidence supporting and not supporting it. The overwhelming effect of trust in organizational climate was reaffirmed. Even employees who had little social media use recognized the potential benefits from social media to build social capital in conjunction with work. The sample of respondents came from a wide range of industries and not specifically from social media-active firms so the findings may be robust. The research replicated a commitment-based HR theory linked to increased productivity. It extended the theory by adding trust in top management and social media use. Some evidence was found that the length of time in years that an organization has had social media correlates with better organizational climate ratings. Stronger correlations were found for trust in coworkers and trust in management with more recent social media actions. This research also provides practical guidance to management concerning potential benefits for moderate employee use of social media at work. The benefits likely include increased trust, knowledge sharing and productivity. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.