Over the last decade, social media has transformed how we communicate in the medical community. Microblogging through platforms such as Twitter has made social media a vehicle for succinct, targeted, and innovative dissemination of content in critical care medicine. Common uses of social media in medicine include dissemination of information, knowledge acquisition, professional networking, and patient advocacy. Social media engagement at conferences represents all of these categories and is often the first time health-care providers are introduced to Twitter. Most of the major critical care medicine conferences, journals, and societies leverage social media for education, research, and advocacy, and social media users can tailor the inflow of content based on their own interests. From these interactions, networks and communities are built within critical care medicine and beyond, overcoming the barriers of physical proximity. In this review, we summarize the history and current status of health-care social media as it relates to critical care medicine and provide a primer for those new to health-care social media with a focus on Twitter, one of the most popular microblogging platforms.