The rapid uptake of social media in social and organizational contexts, combined with growing interest in the broader digital transformation that they enable, raises pertinent questions about uses of these tools for knowledge sharing (KS) in organizations. Social media are now considered one of the few megatrends defining the digital transformation of business across many industries [1]. This article is motivated by two broad phenomena: (1) the importance of informal knowledge-sharing in organizations, and (2) the rapid rise in the variety and prevalence of social technologies. The concept of social media can include both (1) public social technologies such as blogs, wikis, and major public social networking sites (e.g., Facebook, Twitter and LinkedIn), and (2) enterprise social networking technologies used by a host organization (such as Jive, Yammer, SocialCast, and SocialText). The empirical basis of this article is a field study focused on the uses of a variety of social media by knowledge workers from 17 consulting firms. These firms are archetypal knowledgeintensive environments and can be considered harbingers of possible futures in the industry. This work combined four forms of data collection: interviews, micro-studies of practice, documents, and system level data. However, the primary source of data for this research isthe interviews with consultants from multiple management consulting firms. We interviewed 58 consultants and pursued a broad range (maximum variation sample) of age, gender, and position level in the organizations (managers vs. non-managers). The interviews elicited how these workers share knowledge within and across boundaries, and how social media support their knowledge practices. Table 1 outlines the demographics and social media use of the participants. System-level data were particularly useful in capturing the ways that LinkedIn and Twitter were perceived and used. Uses of Facebook and internal social networking systems were self-reported via interviews.