Some time ago an American public health researcher friend here in London showed me some work her team had done examining the social web an vaccine safety rumours.
Short version: similar but false messages about vaccine safety popped up from a handful of sources and quick spread virally, leading people to conclude that there must be some truth to information seen in so many places.
Seems this kind of reaction to / propagation of false or misleading information online is not confined to vaccines. The article below shows similar patterns for political and public security issues and news, too.
Starbird says she’s concluded, provocatively, that we may be headed toward “the menace of unreality — which is that nobody believes anything anymore.”