Rule 1 -- Amazon is a seller.  

Implication 1 -- It is primarily interested in obtaining money from customers (as much as possible, as often as possible).   

Implication 2 - It must sell products, services or experiences to customers to obtain their money

Implication 3 - Amazon must either obtain the products/services/experiences from third parties or produce them itself.

Implication 3 - Amazon is primarily interested in maximizing revenue and/or market share (priorities somewhat specific to Amazon's history), but it is also secondarily interested in maximizing profit.  The implication here being that Amazon is also vitally interested in anything on the procurement side which will maximize profits, such as:

(a) reducing costs of products to Amazon (including a variety of MFN pricing policies);

(b) obtaining exclusive rights to distribute products; 

(c) eliminating any entities or costs on the production side which drive up prices (publishers, agents, external printers, distributors, etc.); and

(d) paying for the production or acquisition of content to be "owned" by Amazon if it can do so at better prices than simply obtaining product from third party owners for resale.

Implication 4 -- Amazon is in a unique position to accelerate sales of individual products, at its own whim, both within its online markets and on its devices.  Placement, placement, placement.  They will "optimize" the visibility of their favored products (whether their own, those of favored producers, or those who pay for placement (just dare to guess how much the big publishers have already paid Amazon for product placement - it'll shock you).

I don't know that I can go too much further in discussing Amazon business models, but the obvious final implication is that "competitors" of Amazon must try to meet Amazon competitively on its own level (product variety, pricing, sales price, ease of sale, e-formats, market features (reviews, cross-suggestions, blogs, e-mail/twitter/other advertising bulletins, etc.), delivery, refund policies, etc.).  First, this means competitors need to coordinate and network into an effectively sized and scoped network of competitors, and vigorously position the network as the "alternative" to Big Bad Amazon.  Second, the competition must keep Amazon on an appropriate level as a competitor.  Vertical integration, preferential pricing/business terms, exclusive deals, etc. all need to be challenged and kept within reasonable antitrust boundaries.

Finally, in terms of authors and content producers, the key to managing Amazon's influence is to try as much as possible to approach Amazon in the same way you approach others in their individual roles (i.e., publisher, online marketplace, etc.).  As a publisher, hold Amazon to the same terms as you would expect traditional publishers to give you, including the same level of support and benefits a traditional publisher would give.  In fact, go further -- sell no more than 5-year licenses, require that the licenses guaranty publication formats and dates, require strong annual sales to prevent OOP status, require that Amazon publish e-books in formats other than just Kindle (or allow you to do so), require that they give you a right to purchase cover art at the end of the license, etc.   They will probably not pay you advances, so you need to push them off of the other tie-ups the traditional publishers have enforced (e.g., license for life of copyright (!), no committed publication date, no commitment to all formats, perpetual tie-ups of foreign rights without timely translation/publication).   Next, pay attention to Amazon marketing commitments.  They only care about the relative margin between the cost of your product and the returns on your product, as well as any advantages they can obtain in excluding others from your product (whether publishers of other formats, translations, foreign markets, or other distribution channels).   They don't directly care about the volume of your sales. If they don't see a potential velocity in the sales of your product, they will put nothing behind it.  In your publishing agreement, get them to make commitments that protect you -- limited term length, commitment to exploit all formats, commitments to website placement and PR, and, if you have any leverage, minimum royalties per year.  Finally, content owners need to turn the pricing preferentials around on Amazon.  Insist on a pricing reset every couple of years, whereby Amazon gives you their current prevailing royalty rate for applicable formats (especially e-book, where the royalty rates have changed several times, but still lag behind what Amazon pays "self-publishing" authors within their preferred price band (which makes sense only if you buy in to the value of "benefits" Amazon will give you as being your publisher).  Don't get locked into compensation rates that won't be changed for the life of your contract.  If they later start paying better, your contract should require that they come back, do an amendment, and pay you better.

In the end, of course, it's a question of leverage.   As independent publisher/self-publishing author, your leverage is Amazon's desire to compete with other marketplaces.  If they want you to sign an exclusive, make it lucrative, guaranteed, and cancellable.   As an author they want to publish, the leverage is that you've been selected as a potentially higher value product and they actually want to own you.  Again, make them pay for the right and at the same time don't give them the right forever or unconditionally.  Everyone will have different leverage, but the good news to remember is that (a) Amazon is not the only game in town (and very much thinks about reacting to and beating competition in every regard), and (b) Amazon is willing to customize and negotiate deals to various degrees, to get what it wants.