Following the tradition of sentiment analysis, many have proposed methods to automatically assess the quality of recommendations or comments based on subjective ratings of their usefulness (Liu et al., 2007;Siersdorfer et al., 2010;Becker et al., 2012;Momeni et al., 2013) or of persuasiveness (Wei et al., 2016).
information thought to be useful does not always prove so, and subjective ratings may be driven by biases.