This book is an innovative attempt to identify and analyse the processes related to social influence in online buying behaviour, with special attention given to the phenomenon of social proof, which is the basis of social media, recommendation marketing, and word-of-mouth (WOM) marketing. It empirically verifies the factors which influence the effectiveness of social proof, and identifies relevant impact factors.

Opening with a literature review of this concept from the perspective of social psychology, sociology, and marketing, this interdisciplinary approach to the issue allows for an in-depth understanding of the mechanisms of the effective use of social proof in contemporary online marketing. Following this, in the context of theoretical considerations, the author analyses the social role and significance of social proof in the buying behaviours of online consumers. The second half of the book presents the results of the author’s quantitative and qualitative research into the effectiveness of social proof. The quantitative research verifies the hypotheses concerning the social role and significance of social proof in buying decisions and identifies the level of confidence in the opinions expressed by other web users. The qualitative research focuses on the empirical verification of the effectiveness of social proof mechanisms. Additionally, attention is given to sensitivity to social proof, i.e. the factors that increase the effectiveness of such messages, from both the sender’s and the recipient’s perspective, as well as the forms and channels of communication.

Written for scholars and researchers interested in the debate on the transparency of activities carried out by companies in the area of online marketing, the book’s detailed analysis of influence utilizing both quantitative and qualitative studies may be of interest to a wider group of academics including economists, psychologists and sociologists.