Stars
The problem with rating systems in general is that only people who feel very strongly about something will take the time to rate it. For a five star scale, that suggests mostly one and five star ratings.
This is why most iPhone apps will have a three star rating. A lower quality app will tend to have about 2.5 stars, and a higher quality app will tend to have about 3.5.
As soon as an app has been rated more than once, it becomes mathematically very unlikely that it will ever see a 1 or 5 star overall rating again. So, it’s nearly pointless to have scales of 5 stars, 10 stars, or 100 stars, when all you really need is: “Liked it, Didn’t Like It, and Neutral”.
