Did the moon landing really happen? Did the royal family orchestrate the death of Princess Diana? Was the American government actually to blame for the September 11 attacks? Do vaccinations cause autism? It appears that in contemporary society one cannot avoid hearing about conspiracy theories and forming their own views. In fact, such conspiracy theories often begin as mere gossip and often become popular interpretations of knowledge. Knowledge is, as Kelley (2002, cited in Liew 2007) states, that which ‘resides in the user [and] happens only when human experience and insight is applied to data and information’. A user, in this sense a conspiracy theorist, selects certain data and information and applies their own human experience, attitudes, and behaviours to it, sometimes subscribing to a conspiracy theory. These theories are then spread in numerous ‘information grounds’ which are ‘environment(s) temporarily created when people come together for a singular purpose but from whose behaviour emerges a social atmosphere that fosters the spontaneous and serendipitous sharing of information’ (Fisher et al. 2006). Once these theories are spread, individuals interact and engage with this information through ‘passive and active information seeking, and information use’ (Wilson 2000). This paper explores the questions: what are conspiracy theories, where are they found, who believes in them, why, and, most importantly, how they are propagated and spread through specific types of information worlds? The answers to these questions can provide insights in regard to areas such as human information behaviours and information grounds. In contemporary society, these information grounds are online, mediated through Internet and Social technologies, and they play an increasingly important role in how conspiracy theories are created, shared, and interacted with. This study used the anti-vaccination movement as an example of one such conspiracy theory. A 2002 study of anti-vaccination websites (long before the prevalence of online social media) found that there is a high probability that parents will encounter elaborate anti-vaccination material on the World Wide Web, [and that] factual refutational strategies alone are unlikely to counter the highly rhetorical appeals that shape these sites (Davies et.al, 2002). The literature points to factors such as perceptions of ‘the other’ (Barkun, 2003), marginalisation (Bruder et al. 2013) power-distance (Swami et al. 2010), self-esteem (Grzesiak-Feldman 2013), paranoid style (Stempel et al, 2007), and monological belief systems (Drinkwater et al. 2012), as all contributing to the belief and propagation of conspiracy theories. Some argue that there should be acknowledgment also that real conspiracies do exist and hence conspiracy theories should not be evaluated in isolation from other theories (Pelkmans & Machold 2011), and that we use the same empirical methods to study it as we use to study other phenomena. Much of the literature on the topic is currently is from psychology, cognitive psychology, cultural studies, and cultural sociology. Although conspiracy theories are predicated on data, information, and knowledge or the lack thereof, there is no examination of it within the information science discipline. The paper presents the results of a study conducted on several publicly available anti-vaccination groups on the social media platform Facebook using content analysis, surveys, and interviews. Data is being analysed using a Constructive Grounded Theory (Charmaz, 2006) approach. Some preliminary results indicate that the following factors are involved in this phenomenon: selective information seeking, distrust of authority, cognitive dissonance or the tendency to seek consistency among their cognitions (beliefs, opinions etc.), and information avoidance, and that they all connect to Elfreda Chatman’s theory of life in the round (1999). There is also some evidence to indicate that the lack of social media engagement by healthcare professionals plays a role also.