Question: Can I post a fictitious “rate this seller” review on Amazon.com, applauding my own company or discrediting my competitor’s?
Answer: Posting a fictitious comment applauding your own company is deceitful, sheker, even if the information itself is correct. It might also involve geneivas da’as, misleading people, since the readers expect these comments to be unbiased reports of other customers and decide to make purchases based on them. (C.M. 228:6; Tzitz Eliezer XV:12) Instead, you should encourage customers who had positive experiences to post reviews. This is ethical even if other customers did not share the same positive experience.
Posting a fictitious comment discrediting your competitor is motzi shem ra, a severe form of lashon hara. In truth, any person has to be careful when posting a negative review. The reason to allow doing so is the need (to’eles) to warn other potential customers about dealing with that company. The Chofetz Chaim (Rechilus 9:2) requires that the information be true, without exaggeration, and with proper intent to warn the consumer – not out of hatred or intent to disparage the seller’s reputation. Therefore, a competitor should avoid posting even a true, negative review, since it is almost impossible for him to have proper intent.
Business Halacha Institute: www.businesshalacha.com