Amazon cannot guarantee you've read the book neither can apple guarantee that you have not used the app on a friends iphone or happened to have the developer as your roommate and seen all the flaws of the app. In any case everyone has a right to opine and it's a matter of their responsibility where and how they got to experience the item under review. Amazon just wants more information on a item (especially in the old days when they did not have the look in option in a book) irregardless of how the person reviewing got it so they can enable you to choose out of the 10000's of titles they have, you are going to buy anyway. Apple on the other hand seem to think that bad reviews or reviews pointing to a free item will impact negatively on the sale and hence they make the reviewing difficult be letting only those who have bought the app review. That to me is bad for the consumer. As a great comment here went, how about them removing all the five star reviews from the developers themselves.
Give me break, I used caps from empasis I did not shout in your ear, I am not bothered by caps when used spearingly, so If you are DON'T READ THEM. You 've missed the points I made completely, they flew over you, I suggest you re-read what I wrote and make more of an effort to understand my point of view. It's not a matter if you can or cannot buy an app or a book elsewhere, even if you bought the book elsewhere the fact that you are reviewing for amazon and letting that become property of amazon means that you want to take part in the amazon reviewing community and this is what amazon want to enable you to. The fact that you cannot buy an app elsewhere DOES NOT mean that you cannot be familiar and have an opinion about it in any 100s of ways that may have come about. Unless you can equate "buying an item"="having a valid opinion on it" your argument doesn't hold ground at all. Apple is wrong in doing that. If I have an opinion on an item and I want to express it they should allow me. Paying 20 $ for a 0.9 app that will buy you twenty reviews or so, and the developper can then easily ridge the system by submitting all 20 of them positive ones. So? So, nothing. So to me their decision to ban non paid reviews is a. not going to impact much or b. impact on a negative way for the buying public. If someone has a valid point to make and writes a good review then they should let all reviews in and make me the judge of who is making sense or not, having bought the app doesnt mean you are going to write a valid review - this is just a way to appease developpers, have more sales and generally higher rated apps, but ALSO a way to disable the buyers from making a correct choice by barring diversity in the reviews. Of course it seems you won't understand this time around either, but I wouldn't really expect you to.
I read your comment and you're missing one big point. This isn't some freedom of the press issue - Apple owns and operates the App Store - they can decide whatever the heck they want to put on there. Apple is simply guaranteeing the "developper" a fair shake from the iPhone/iPod Touch community. Apple is not doing anything to bad reviews - they are just not going to let you get on there and complain about an app because you don't like the price or the screen shots make it seem worthless or you think you have a better app. When was the last time a movie critic wrote a review based on a trailer? Yeah, never. It's called being responsible and Apple is doing what it can to prevent irresponsible people from taking advantage of the system. (It's much harder to kick out developer friendly reviews as there isn't some tag that would let them know that so they'd have to go through and actually read every single review of every single app - that's never going to happen).
EDIT - how exactly is the "developper" going to "ridge" the system? You think they are going to go and create 20 different accounts, all with different credit cards and then buy their app 20 different times (this costs them money seeing as how Apple gets 30% of the profit) just to produce 20 reviews that in the end are going to have a marginal % impact? You're reaching, a lot...