Computer analysis spots the fingerprints that fraudulent raters leave behind.
Searching for hotels in cities they’ve never visited, people often turn to customer-written reviews on websites such as TripAdvisor. But how do they know those reviews weren’t written by the hotel manager, or by someone paid to post fake opinions online? The U.S. Federal Trade Commission has issued fines when it has uncovered such “opinion spam,” but there’s no easy way to spot it.