Well, the same thing is happening as a customer shifts from using a desktop/laptop to using tablets, then from using tablets to mobile devices, then from mobile devices to apps. When you unbundle e-commerce (and you need to unbundle it, folks, or you are like the catalogers of 2003 who thought that their business was multi-channel and that you analyzed it as one unit), you quickly see that the tablet is the gateway to a mobile phone, that the mobile phone is the gateway to an app, and once the customer is using the app, the customer begins to pull away from the desktop/laptop experience.
There are three cases where you'll never observe this phenomenon.
- You won't see this if you measure conversion rates - you will be blind to ecosystem changes.
- You won't see this if your customer is older than 45 years old.
- You won't see this if you believe that e-commerce is a sum of old-school e-commerce and modern smart phones using apps as the portal to your business.
Analyze customers longitudinally. You'll see that e-commerce is gaining sales from old-school channels (catalog, retail, mostly retail these days), and that e-commerce is bleeding out into mobile. In other words, e-commerce is being torn in half. And when mobile (smart phones, not tablets, tablets behave too much like desktop/laptop) and younger customers take over, look out, folks.
The data I see in mobile looks the same as the data I saw 10+ years ago when analyzing the transition from catalogs to e-commerce. Study what happened during that era of channel shift, if you want a preview of what mobile is going to do to e-commerce.