[busterarm]

Somewhat. A lot of review systems are designed to contact you asking for a review at the exact time you're most likely to leave a good review. The companies then optimize the whole customer interaction around that experience. To actually go back and edit that review when things change isn't always easy.

The overwhelming majority of all other reviews are either the Amazon variety (so a paid endorsement, usually) or from total cranks. People don't really often leave unsolicited reviews.