The rise of social media has democratized content creation and has made it easy for anybody to share and to spread information online. On the positive side, this has given rise to citizen journalism, thus enabling much faster dissemination of information compared to what was possible with newspapers, radio, and TV. On the negative side, stripping traditional media from their gate-keeping role has left the public unprotected against the spread of disinformation, which could now travel at breaking-news speed over the same democratic channel. This situation gave rise to the proliferation of false information specifically created to affect individual people's beliefs, and ultimately to influence major events such as political elections; it also set the dawn of the Post-Truth Era, where appeal to emotions has become more important than the truth. More recently, with the emergence of the COVID-19 pandemic, a new blending of medical and political misinformation and disinformation has given rise to the first global infodemic. Limiting the impact of these negative developments has become a major focus for journalists, social media companies, and regulatory authorities.
The tutorial offers an overview of the emerging and inter-connected research areas of fact-checking, misinformation, disinformation, “fake news”, propaganda, and media bias detection, with focus on text and on computational approaches. It further explores the general fact-checking pipeline and important elements thereof such as check-worthiness estimation, spotting previous fact-checked claims, stance detection, source reliability estimation, and detecting malicious users in social media. Finally, it covers some recent developments such as the emergence of large-scale pre-trained language models, and the challenges and opportunities they offer.