[hammock]

Offering a five stars to the rater can cause them to treat it as a thumbs up/thumbs down (as your parent comment alludes to when he references "game theory" and giving a one-star), with one star being the most powerful thumbs down, the obvious choice.

The other alternative is for users to actually SORT and RANK all products in that category that they have reviewed. Not a tenable solution.

Side comment, the Yelp histograms ARE useful... but that is more of a side effect/emergent from a bad rating scheme than anything else. Because people are using the stars not ideally, the histogram gives you insight into that. So it's not a bad solution, but a better solution would be something other than the stars.