This study makes an attempt to bridge the research gap by
quantifying the effect of online user reviews on the number of
online sales. Previous studies have indicated that the valence of
online user-generated reviews may influence sales of books and
digital products (Chevlier & Mayzlin, 2006; Ghose & Ipeirotis,
2006; Ye et al., 2009a, 2009b). We thus propose the following
hypothesis on the basis of their findings.