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.
Giving away facts, good for business (IMDB, Prices, etc)
Giving away subjective content, not good for business (Reviews)
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.
True, but IMDB was acquired mostly to provide data to Amazon.com. For 15K, you can get access 'legally' to IMDB data.
As for IMDB Pro, serves mostly the film/tv industry itself not consumers, where the money is.
I don't think I've ever seen this API used in a legitimate way. I frequently see "product review" sites that are nothing more then ads and amazon reviews. Seems like by removing it, they will effectively clean up a large amount of review spam, which is fine with me.