  A new era of Information Warfare has arrived. Various actors, including
state-sponsored ones, are weaponizing information on Online Social Networks to
run false information campaigns with targeted manipulation of public opinion on
specific topics. These false information campaigns can have dire consequences
to the public: mutating their opinions and actions, especially with respect to
critical world events like major elections. Evidently, the problem of false
information on the Web is a crucial one, and needs increased public awareness,
as well as immediate attention from law enforcement agencies, public
institutions, and in particular, the research community. In this paper, we make
a step in this direction by providing a typology of the Web's false information
ecosystem, comprising various types of false information, actors, and their
motives. We report a comprehensive overview of existing research on the false
information ecosystem by identifying several lines of work: 1) how the public
perceives false information; 2) understanding the propagation of false
information; 3) detecting and containing false information on the Web; and 4)
false information on the political stage. In this work, we pay particular
attention to political false information as: 1) it can have dire consequences
to the community (e.g., when election results are mutated) and 2) previous work
show that this type of false information propagates faster and further when
compared to other types of false information. Finally, for each of these lines
of work, we report several future research directions that can help us better
understand and mitigate the emerging problem of false information dissemination
on the Web.
