Credits: Ad Age By: Michael Learmonth
'Online reviews can make or break a local business, which is why the incentive to cheat with paid-for, malicious or fraudulent reviews is so great. Weeding out fraud is an inexact science; sites such as TripAdvisor, Google+ Local and Yelp use a mix of algorithms and human moderators to separate fraudulent reviews from genuine.
Of all the major review sites casting a dragnet, Yelp stands out for its aggressiveness in trying to catch fraudsters: 20% of reviews written and submitted are never displayed.'
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