With over a billion mobile web users, over 10 billion mobile apps downloaded, and mobile device sales increasing worldwide, the trend is definitely mobile.
Originally, designers and developers would create a full standard website or app built for a desktop browser and then gradually scale back and remove content and features as the viewport was reduced. Unfortunately, this tends to create a great deal of code bloat and broken functionality since many of the “cool features” that work well on a desktop won’t scale down to a mobile device nicely.
Now, websites and apps are built for the smallest device with 1.0 like functionality. Then the scope, features, and view scale are increased to utilize the real estate and power of the larger devices, such as desktops and iPads. This creates a product that feels more polished and complete in the mobile arena as well as others.