The Dark Side of the Word-of-Mouse Effect- An experimental study of how negative information in today?s social media can influence consumer perception As a result of the electronic revolution of information dissemination, social media as a phenomenon has come to play an important part, both in society at large but also when it comes to business and marketing. Nowadays, knowledge and opinions about brands and products are spread by reputation through a wide range of social media platforms, a phenomenon which in the literature is referred to as word-of-mouse or electronic word-of-mouth (eWOM).The purpose of this paper is to investigate how people?s opinions towards a company and its product are affected by negative information in terms of eWOM. Or more precisely, whether or not there is a difference in this effect depending on information content, concerning company values on the one hand and product attributes on the other.This was done in an experimental setting where two groups of respondents were subjected to fictitious information of different types using established social media platforms.