The 2nd edition of the RDSM workshop will particularly focus on online information disorder and its interplay with public opinion formation. Information disorder has been categorised into three types: (1) misinformation, an honest mistake in information sharing, (2) disinformation, deliberate spreading of inaccurate information, and (3) malinformation, accurate information that is intended to harm others, such as leaks. The spread of this information can play an important role in shaping public opinion, as well as the formation of public opinion can feed back into the production and sharing of information disorder.

The challenges posed by online information disorder and its ability to shape public opinion has evoked the occurrence of important political phenomena of worldwide impact in recent events. This is the case of recent political events such as Brexit and Trump’s election, where social media played a significant role in shaping public opinion and issues now known as “fake news” and “post-truth” had an impact that is yet to be understood.

It is a fact that social media is an excellent resource of mining all kind of information varying from opinions to actual facts. However, it is also fact that not all pieces of information are reliable and thus their truth is highly questionable. One such category of information types are rumours where the veracity level is not known at the time of posting. Although rumours can be true many of them are classified as false and such false rumours are a powerful tool used to manipulate public opinion. It is therefore very important to detect and verify false rumours before they are spread and influence the public opinion. In this workshop the aim is to bring together researchers and practitioners interested in social media mining and analysis to deal with the emerging issues of rumour veracity assessment and manipulation of public opinion.