Ratings - what do they really say?

Here's a really good example of the different things simple ratings can tell you. Jared Spool on User Interface Engineering shows us that by comparing ratings of the same product on different websites you can get a very conflicting story.

Essentially one website was that of a bricks and mortar shop and the other was Amazon. Taking an example review from each website we could see that each review told essentially the same story but on one the product got 3 out of 5 stars and the other only 1 out of 5 stars.

The reason? Not the product but the customer service of the retailer.

Internally, for all events we rate based on a number of different KPIs. This allows us to find out what parts of the event performed well and which parts didn't. These ratings are not public, but it makes me think if they were to be made public, how would they be displayed? I wouldn't like to have five different 5-star ratings, but as we can see above, a single 5-star rating may be inadequate.