Social network sites are a new communication channel to convey CSR information. They are interactive channels that let users participate, spread content and generate positive and negative electronic word-of-mouth about companies that can dramatically affect their reputation and future business. To identify the factors behind this behaviour, we designed a causal model to explain the intention to both comment on and share a negative corporate social responsibility news posted on Facebook. We included the following as explanatory variables: social consciousness, environmental (...) consciousness, information usefulness, corporate image and attitude towards sharing and commenting on CSR news. We surveyed 208 Facebook users who evaluated a fictitious news item about an environmental issue. We observed that social and environmental consciousness influences the usefulness of information and the attitude towards behaviour, which may explain the eWOM intention of the specific news. However, corporate image can cause people to refrain from generating eWOM and spreading the news on their friend social network. (shrink)