Channel 4 news Los Angeles did a story on YELP the online review company due to all the complaints lodged against them for their unscrupulous methodical posting methods of reviews. Negative reviews are posted in a conspicuous place on the page, whereas positive reviews are often HIDDEN from the review page where they cannot be seen or found.
If you really look and are computer savy, you will eventually find a barely visible "not recommended" link that you have to click before you can see the hidden positive reviews come up. What would Yelp's motive be in selectively displaying vs. hiding reviews, you ask? MONEY! Yelp later contacts the business owners by phone offering to improve their ratings "FOR A FEE." Sounds like an alleged crime of blackmail to me!