As a simple example of this, let us imagine for a minute that Amazon and Google go to war. Google drops all search results that point to Amazon products or products in the Amazon marketplace and direct those searches to competitors and competing marketplaces. Google also changes Chrome so that entries into the url bar that are not explicitly for amazon domains do not match or return any amazon domain or product.

Since "Google is not a monopoly" I am sure no one would have a problem with this behavior... :)