Uh...Yes and No.

One of the worst things that can happen to a company is having its image portrayed in a negative light. For instance if a brand is trying to be high-end, but has its products adopted by low-end consumers, they'll never sell to a high-end consumer again... A good example is clothing trends.

If the merchants keep a tight leash on the "reviews" then it could be a good thing. Must customers are fairly lazy or busy also. In general they will type a couple words about a decent item, but will not make a video about a great item.

The merchants and the reviewers should stay within their respective specialties.