I've never had Amazon remove reviews I'd written that were negative about a product. However I did have them remove a review that contained a very mildly critical dig at Amazon themselves:<p>I'd ordered some electrical sleeving of a certain radius and got sent instead sleeving of that diameter. I returned the item and got it sent out again –and the exact same thing happened.<p>In my review of the product, I mentioned this as an aside and said "someone at Amazon doesn't know the difference between radius and diameter". Hardly a vitriolic outburst, but Amazon pulled the review.<p>In consequence, I spent a therapeutic hour or so deleting all the hundred+ reviews I'd previously left on Amazon [several of them highly ranked]. I don't mind if they want to censor unfair/dishonest/libellous reviews, but if they feel the need to censor even the mildest criticism of themselves, they can get fucked. I'm not going to provide them with free copy for their site, any more.
The value of their review system has taken a hit from the sleazy seller practice of giving free and heavily-discounted products for (surprise!) uniformly favorable reviews. I've seen products with over 100 reviews of which more than half <i>admitted</i> to getting the product "free or discounted".