Two rather computational papers come to mind. When you put the two together, you get close to quality's effect on demand. Archak, N., Ghose, A., et al. Show me the money!: deriving the pricing power of product features by mining consumer reviews. Proc. KDD, 2007. 56–65. http://doi.acm.org/10.1145/1281192.1281202 Otterbacher, J. 'Helpfulness' in online communities: a measure of message quality. Proc. CHI, 2009. 955–964. http://doi.acm.org/10.1145/1518701.1518848 Cheers, Eric