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 taxonomy 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. 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.
Credibility Assessment. Buntain and Golbeck @cite_88 compare the accuracy of models that use features based on journalists assessments and crowdsourced assessments. They indicate that there is small overlap between the two features sets despite the fact that they provide statistically correlated results. This indicates that crowdsourcing workers discern different aspects of the stories when compared to journalists. Finally, they demonstrate that models that utilize features from crowdsourcing outperform the models that utilize features from journalists. @cite_155 present a set of indicators that can used to assess the credibility of articles. To find these indicators they use a diverse set of experts (coming from multiple disciplines), which analyzed and annotated 40 news articles. Despite the low number of annotated articles, this inter-disciplinary study is important as it can help in defining standards for assessing the credibility of content on the Web. @cite_213 study the interplay between fact-checkers and rumor spreaders on social networks finding that users are more likely to correct themselves if the correction comes from a user they follow when compared to a stranger.
@cite_88 @cite_213 @cite_155
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Evaluating information accuracy in social media is an increasingly important and well-studied area, but limited research has compared journalist-sourced accuracy assessments to their crowdsourced counterparts. This paper demonstrates the differences between these two populations by comparing the features used to predict accuracy assessments in two Twitter data sets: CREDBANK and PHEME. While our findings are consistent with existing results on feature importance, we develop models that outperform past research. We also show limited overlap exists between the features used by journalists and crowdsourced assessors, and the resulting models poorly predict each other but produce statistically correlated results. This correlation suggests crowdsourced workers are assessing a different aspect of these stories than their journalist counterparts, but these two aspects are linked in a significant way. These differences may be explained by contrasting factual with perceived accuracy as assessed by expert journalists and non-experts respectively. Following this outcome, we also show preliminary results that models trained from crowdsourced workers outperform journalist-trained models in identifying highly shared "fake news" stories. With the rapid growth of social media, rumors are also spreading widely on social media and bring harm to people's daily life. Nowadays, information credibility evaluation has drawn attention from academic and industrial communities. Current methods mainly focus on feature engineering and achieve some success. However, feature engineering based methods require a lot of labor and cannot fully reveal the underlying relations among data. In our viewpoint, the key elements of user behaviors for evaluating credibility are concluded as "who", "what", "when", and "how". These existing methods cannot model the correlation among different key elements during the spreading of microblogs. In this paper, we propose a novel representation learning method, Information Credibility Evaluation (ICE), to learn representations of information credibility on social media. In ICE, latent representations are learnt for modeling user credibility, behavior types, temporal properties, and comment attitudes. The aggregation of these factors in the microblog spreading process yields the representation of a user's behavior, and the aggregation of these dynamic representations generates the credibility representation of an event spreading on social media. Moreover, a pairwise learning method is applied to maximize the credibility difference between rumors and non-rumors. To evaluate the performance of ICE, we conduct experiments on a Sina Weibo data set, and the experimental results show that our ICE model outperforms the state-of-the-art methods. A frequent problem when dealing with data gathered from multiple sources on the web (ranging from booksellers to Wikipedia pages to stock analyst predictions) is that these sources disagree, and we must decide which of their (often mutually exclusive) claims we should accept. Current state-of-the-art information credibility algorithms known as "fact-finders" are transitive voting systems with rules specifying how votes iteratively flow from sources to claims and then back to sources. While this is quite tractable and often effective, fact-finders also suffer from substantial limitations; in particular, a lack of transparency obfuscates their credibility decisions and makes them difficult to adapt and analyze: knowing the mechanics of how votes are calculated does not readily tell us what those votes mean, and finding, for example, that a source has a score of 6 is not informative. We introduce a new approach to information credibility, Latent Credibility Analysis (LCA), constructing strongly principled, probabilistic models where the truth of each claim is a latent variable and the credibility of a source is captured by a set of model parameters. This gives LCA models clear semantics and modularity that make extending them to capture additional observed and latent credibility factors straightforward. Experiments over four real-world datasets demonstrate that LCA models can outperform the best fact-finders in both unsupervised and semi-supervised settings. Crowdsourcing platforms enable to propose simple human intelligence tasks to a large number of participants who realise these tasks. The workers often receive a small amount of money or the platforms include some other incentive mechanisms, for example they can increase the workers reputation score, if they complete the tasks correctly. We address the problem of identifying experts among participants, that is, workers, who tend to answer the questions correctly. Knowing who are the reliable workers could improve the quality of knowledge one can extract from responses. As opposed to other works in the literature, we assume that participants can give partial or incomplete responses, in case they are not sure that their answers are correct. We model such partial or incomplete responses with the help of belief functions, and we derive a measure that characterizes the expertise level of each participant. This measure is based on precise and exactitude degrees that represent two parts of the expertise level. The precision degree reflects the reliability level of the participants and the exactitude degree reflects the knowledge level of the participants. We also analyze our model through simulation and demonstrate that our richer model can lead to more reliable identification of experts.