Abstract: Social media have given the opportunity to users to publish content and express their opinions online in a fast and easy way. The ease of generating content online and the anonymity that social media provide have increased the amount of harmful content that is published. A great amount of fake news, hoaxes, hurtful comments, inaccurate reviews and offensive content is published and propagated every day in social media. Bots play also a key role in disseminating false claims and hate speech. In this keynote I will describe some of the machine learning based intelligent systems that address the problem of detecting harmful information, with special emphasis on fake news and hate speech. Moreover, I will describe some of the shared tasks that have been organised in our research community for instance at the PAN Lab, where given a Twitter feed, the aim has been to identify whether its author is a bot (2019), or s/he is keen to be a spreader of fake news (2020). At SemEval the HatEval shared task (2019) focused on identifying hate speech towards immigrants and women.

Biography: Paolo Rosso is full professor at the Universitat Politecnica de Valencia, Spain where he is also member of the PRHLT research center. His research interests focus mainly on author profiling, irony detection, fake reviews detection, plagiarism detection, and recently hate speech and fake news detection. Since 2009 he has been involved in the organisation of PAN benchmark activities at CLEF and at FIRE evaluation forums, mainly on plagiarism / text reuse detection and author profiling. At SemEval he has been co-organiser of shared tasks on sentiment analysis of figurative language in Twitter (2015), and on multilingual detection of hate speech against immigrants and women in Twitter (2019). He is co-ordinator of the activities of FIRE and IberEval evaluation forums. He has been PI of national and international research projects funded by EC and U.S. Army Research Office. At the moment, in collaboration with Carnegie Mellon University, he is involved in a project funded by Qatar National Research Fund on author profiling for cyber-security. He serves as deputy steering committee chair for the CLEF conference and as associate editor for the Information Processing & Management journal. He has been chair of *SEM-2015, and organisation chair of CERI-2012,CLEF-2013 and EACL-2017. He is the author of 400+ papers, published in journals, book chapters, conference and workshop proceedings.