Rick Zeman writes: Consumer reviews are powerful because, unlike old-style advertising and marketing, they offer the illusion of truth. They purport to be testimonials of real people, even though some are bought and sold just like everything else on the commercial Internet. Yet it is all but impossible to tell when reviews were written by the marketers or retailers (or by the authors themselves under pseudonyms), by customers (who might get a deal from a merchant for giving a good score) or by a hired third-party service. The New York Times tells of the rise and fall of one such hired third party service who had has been so successful planting paid fake reviews that he no longer trusts any online review. He should know. Because of him and his kind, it's estimated that one third of online reviews are fake.