When people are shopping online, many rely on reviews written by previous buyers to help steer them in the right direction. But it seems some of those reviews may not be as honest as we think.

In fact, some product manufacturers are actually paying shoppers to write them -- albeit in a roundabout way.

The New York Times points to the example of VIP Deals, which sells leather cases for the Kindle Fire. The popularity of those cases recently soared after hundreds of positive reviews suddenly showed up on Amazon -- in fact, 310 out of 335 reviews for the cases last week got five stars.

But after the Times interviewed some customers, it learned that when they got the cases, the package included a note that invited them to "write a product review for the Amazon community. In return for writing the review, we will refund your order so you will have received the product for free."

Amazon's guidelines prohibit compensation for customer reviews -- so after the Times sent the company a copy of the note, it deleted the VIP Deals product page.

The Federal Trade Commission is also taking notice. Its rules state that when there's a connection between a merchant and someone promoting its product that affects the endorsement’s credibility, it must be fully disclosed.

The regulatory agency has already cracked down on a few companies for deceitful hyping and it suspects there are many more. “Advertising disguised as editorial is an old problem, but it’s now presenting itself in different ways,” said Mary K. Engle, the FTC's associate director for advertising practices. “We’re very concerned.”

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