How to predict if a brand will spread by word of mouth

From the Bulldog Reporter, about a new study from American Marketing Association:

The analysis that appears in the August 2013 issue of the American Marketing Association's Journal of Marketing Research shows that the nature of word-of-mouth is fundamentally different between offline conversations and online discussions. While the main motivation of consumers to spread the word on brands in offline conversations is to share emotions such as excitement and dissatisfaction, in online discussions, which usually involves "broadcasting" to many people (e.g., Twitter), their main driver is to express their uniqueness and status. 

Consider, for example, the role of product differentiation—an attribute that received much attention in marketing and economics due to its strategic role in competition. This study suggests that by mentioning a highly differentiated brand in a conversation the consumers can express her uniqueness. 

Thus, it is expected that (1) the higher level of differentiation, the higher is the word-of-mouth, and (2) that this relationship is stronger in an online setting.