Determining the number of fake reviews on the Web is difficult. But it is enough of a problem to attract a team of Cornell researchers, who recently published a paper about creating a computer algorithm for detecting fake reviewers. They were instantly approached by a dozen companies, including Amazon, Hilton, TripAdvisor and several specialist travel sites, all of which have a strong interest in limiting the spread of bogus reviews.

(via Ferreting Out Fake Reviews Online – nytimes.com)

Ironically, it seems that machines may be better at detecting fake reviews than people.