As a consumer review Web site, Yelp is so big and influential that it has given rise to a small, semi-underground group of entrepreneurs who, for a fee, will post a rave about your company. Others will post a negative review about your rivals.
Obviously, Mechanical Turk work is not a path to quick riches. Panagiotis G. Ipeirotis, an associate professor of information, operations and management sciences at the Stern School of Business at New York University, who has studied the site, says his polling of Turk workers found that many were based in India and often earned $2 to $3 an hour.
Interesting article about a business that I didn't know existed.