At least they realize it. Amazon book ratings have a similar problem, to a lesser degree. You really have to dig into the individual reviews to get any reasonable ratings info. I find, at least for technical books, that comparing the price the book is being sold for used to the new price is one of the more accurate ways of determining if a book has legitimate value.
Actually, Amazon's review & rating system seems to be one of the few that works well. Seeing the distribution and reading the most useful positive and negative reviews works really well in my experience.
It's not just about good vs bad. It is also the fact that i can see what people didn't like it. Often there are downsides that are a big deal to some, those that rate low which may or may not apply to me.
