I think they learned that giving away reviews was giving away free content, and wasn't helping drive more people to the Amazon site. Can't say that I blame them for pulling the plug on that.
Care to substantiate that? For instance, IMDB's facts are it's business, which is why some of those facts are reserved for paying members. Likewise, the fact Amazon has free public reviews is a big reason that people visit Amazon, just as the subjective blog posts of 37 Signals contribute significantly to their success.
