This paper examines why parties adopt different electoral strategies by analyzing declarations and statements released by official party staff, activists and voters on social media and social network sites (Twitter, Facebook, etc). Focusing on the 30 days prior to the 2014 European Elections campaign, we analyze the on-line campaign styles employed by rival parties within 8 European countries (Austria, Great Britain, France, Germany, Ireland, Italy, Luxemburg, and Spain) in order to detect which incentives bring them to rely either on positive or negative campaigning based on character valence issues. We draw from an original dataset built applying a semi-automated tool for content analysis, ReadMe, to measure the degree of negative and positive messages related to valence or policy issues.
