E-cigarettes have been sited as dangerous to the public's health because of the multiple carcinogens found in e-liquids, and because of their potential to serve as a gateway drug to combustible cigarettes. The use of e-cigarettes in the US has been increasing dramatically among both youth and adults since data collection began in 2010. Much of this increase in use has been linked to the mass marketing that e-cigarette companies have employed through television advertisements, on print advertisements, and advertisement on social media. The voice of public health professionals is also divided between those who advocate for e-cigarette use as a tobacco harm-reduction device, and those who advocate for prevention of e-cigarette use. Currently, the conversations and ideas about e-cigarettes among the public are not well understood. The current study seeks to examine conversations about e-cigarettes on a popular social networking site, Twitter. Tweets related to e-cigarettes were collected using technology called the Social Media Analytic and Research Testbed dashboard. A total of 193,051 tweets were collected between October 2015 and February 2016. Of the total tweets, a random sample of 1,000 tweets were selected and manually coded for information regarding source characteristics and message characteristics. The source characteristics that were measured included: (a) Individuals, (b) Organizations, and (c) Twitter-Verified Celebrities. Within the Individuals and Organizations categories, various details were coded such as whether the user identified as a child, student, parent, potential robot account, business entity, news/media source, or health information provider. The results of the study showed that a majority of users in the sample identified as Individuals (89.6%) and the remainder identified as Organizations (10.4%). The highest percent of individual accounts discussing e-cigarettes were those coded as Potential Robot Accounts (71.5%) and children (9.9%). Among organizations, the highest percent of accounts discussing e-cigarettes were coded as Business Entities (75.9%) and News/Media Sources (21.2%). Overall, a majority of profiles posted positive sentiments about e-cigarettes (68.1%). A chi-square test revealed that profiles coded as Organization, are significantly more likely to tweet positive sentiments, compared to Individual profiles: X2 (1, N=680) = 639.09. Additional sentiments that were most prevalent included mentions of Stigma (11.7%) and Harmfulness (6.7%). The highest percent of information codes that were discussed include Advertisements (7.2%) and E-Liquid Flavors (7.0%). Sentiments toward e-cigarettes continue to be very positive. More research should be conducted to investigate the high percentage of potential robot accounts and how these accounts are affecting the conversations happening through social media.