The one thing big eCommerce companies do best is keep their momentum going. They know exactly what the lifetime value of each customer is, and that number is very high because of their efforts to keep engaging and re-engaging their customers.
You are probably aware of their efforts to do this through direct incentives to buy more than once in programs like Amazon Prime, but maybe not through more subtle means to “prime” customers to buy other things.
One great recent example of this was when I purchased a new solid state hard drive from Amazon to speed up my PC. Amazon “knew” I would likely also need a USB tethering cable to do my upgrade — an algorithmic guess, but effective nevertheless. This was something I saw, registered, and came back to buy once I knew I needed it, as I knew exactly where to get it.
Amazon uses its own sales history data to algorithmically upsell its house lists for explosive growth.
Sure, Amazon doesn’t really have the same level of on-demand customer service that a smaller electronics eCommerce shop has, like Newegg, for example, but they make up for that difference using marketing automation to register the user’s need at the right time before they seem to need it — using subconscious programming — and after having leveraged the cloud technical contributions made by the public to overt the need for expensive margin-crushing technical customer support.
Because of this attention to detail for their customers, Amazon spends a whole lot more to obtain their customers than their competition but gets a whole lot more return.