[poorman]

I reference this article constantly at Untappd.

When we were building the NextGlass app, I took much of this into consideration for giving wine and beer recommendations.

We recently ran the query on the Untappd database of 500 million checkins and it yielded some interesting results. The "whales" (rare beers) bubbled to the top. I assume this is because users who have to trade and hunt down rare beers are less likely to rate them lower. The movie industry doesn't have to worry about users rating "rare movies", but I would think Amazon might have the same issue with rare products.

[chris_va]

There is an interesting phenomenon of exclusivity/sunk-cost boosting ratings for rarer or harder to acquire items.

That is also a problem with movie ratings (I just noticed that you mentioned movies). Critics (and audiences) at pre-screenings are generally significantly more favorable to a movie than an equivalent group in a normal theater. I would not be surprised if the same thing applied to foreign movies, and other types of "whales".

[infomofo]

Untappd is also weird because you know that the producers of some of these small brewery beers actually look at these checkins. A lot of the beer drinkers I know will prefer to not rate a beer instead of giving it a sub-3 rating.