  I present evidence that communication between marketplace participants is an
important influence on market demand. I find that consumer demand is
approximately equally influenced by communication on both formal and informal
networks- namely, product reviews and community forums. In addition, I find
empirical evidence of a vendor's ability to commit to disclosure dampening the
effect of communication on demand. I also find that product demand is more
responsive to average customer sentiment as the number of messages grows, as
may be expected in a Bayesian updating framework.
