Delusions are said to fall on a continuum representing the extreme end of a spectrum of psychotic-like traits. Consistent with this view is the notion that milder forms of delusional beliefs are observable within the general population, manifesting as unusual ideas which do not cross the thresholds for clinical symptoms, but which might represent a vulnerability for psychotic disorder. In the pre-Internet age, unusual or bizarre beliefs (such as conspiracy theories) would have had fewer opportunities for social acceptance, as the proponents would have less chance to share their ideas with like-minded people. Indeed, part of the DSM-V definition of delusions stipulates that delusions are “not understandable to same-culture peers”. However, the rise of social media presents new platforms for socially unacceptable beliefs to gain exposure and endorsement from like-minded others, who are no longer limited by geographical constraints. Evidence suggests that conspiracy theories and other contentious beliefs have grown in popularity due to the ease with which they are propagated and reinforced through online platforms. In this chapter, we review the current evidence on the continuity between delusions and conspiracy beliefs. We also explore whether social media and other online platforms make vulnerable individuals more likely to adopt unsound beliefs and consider the effects this might have on mental health as well as the broader social and political implications.