From WSJ this week:
“One of the Web’s little secrets is that when consumers write online reviews, they tend to leave positive ratings: The average grade for things online is about 4.3 stars out of five. Many companies have noticed serious grade inflation. Google Inc.’s YouTube says the videos on its site average 4.6 stars, because viewers use five-star ratings to “give props” to video makers. Buzzillions.com, which aggregates reviews from 3,000 sites, has tracked millions of reviews and has spotted particular exuberance for products such as printer paper (average: 4.4 stars), boots (4.4) and dog food (4.7).”

The lesson here is that you need to understand the “why” behind the numbers to really understand what consumers are thinking and saying about your products and brands. Otherwise you might be like me and think that all printer paper is about the same.