The strongest propulsion for conspiracist thought is, perhaps, the ready access to publication of ideas (sans vetting) that is provided by the internet. Just as the internet helps spread conspiracy theories, so too does the internet embolden the conjecture and strengthen the ideological resolve of the conspiracist.
The Flat Earth conspiracy movement can be mapped out alongside the history of YouTube. The ability to easily create and post videos gives the conspiracist the opportunity to claim anything they like, post it online, and believe that they are, in fact, experts by virtue of their publish.
Here are some examples of Flat Earthers on Youtube:
Flat Earth conspiracists are plugged in, media savvy to some extent, but just as convinced of a number of paradoxical conspiracist beliefs that lends to them the belief that they are ‘awake’ and all others are ‘sheep.’ More than anything else, if you are a ‘promoter’ of an ideology (or conspiracy theory) rather than a mere ‘adherent’ then they are likely to maintain greater zeal.
So, if considering the path an idea used to take (pre-internet) to become a relatively potent anomalistic belief (i.e. ghosts, auras, etc.), one can look back at communities and tribes spreading lore, myth, legends, and stories over millennia. With the written word, such messages can be transmitted over time, Radio meant that ideas could be transmitted over vast expanses of space. Video, even images of the fantastic or impossible moving in time and space, render ideas believable on a visceral level. What the internet, in general, adds to the history of human media is the potential for exponential spread of ideas, as well as incalculable increases in levels of adoption of ideas, and the identification with an idea or an ideology. The internet not only offers access to a vast array of ideas, but social media specifically helps link idea with identity: rendering any identified idea all the more potent and any objection to said idea to become more readily interpreted as a personal affront.
YouTube is social media, is visual, and is produced by individuals who thus identify as producers of their content. They are not anonymous (except for those who are) and most people post video blogs (vlogs) with the assumption that they will have an audience. Regardless of how fleeting and ill founded an idea may be, once a vlogger posts a video blog about it on YouTube, it is a part of them. Any questions suggesting logical fallacies or factual errors are tantamount to an attack on their identity. They are the producer.
The viewer of such a video may post a link on Facebook. They are consuming, but also inviting friends to consume as well (this metaphor seems odd in this context but it seems to be necessary to acknowledge the consumer model). Though the producer of the video does not see comments left by friends or family but the consumer does, and that consumer sees people that care about them share their opinions on the subject as more relevant than would any video blogger with no personal relationship with said individual’s family or friends. The result, usually, is that YouTube vloggers remain steadfast and those who post to Facebook (or other social media) either fail to adopt or do so in secret. One exception would be posting via instant messenger to a like-minded friend. Regular reinforcement of an uncommon belief may not be necessary for adoption or extended adherence, but constant ridicule and/or criticism from significant others will likely end with either the dissolution of the belief or (unfortunately) the dissolution of the relationship.
If you consider conspiracist ideation in a way similar to cult indoctrination it becomes clear that YouTube is one of the most effective means of indoctrination for those who are active vloggers. For many reasons, some of which I have not gone into here, vloggers can conjecture themselves into ever-increasing states of ideological (and conspiracist) fervor.