Because they're more mobile, they'll be enjoyed for more casual uses. The , for example, is a great example of the kinds of uses people will gravitate toward on small tablets.

The new and the newly improved , both new to the Jelly Bean version of Android and first launched on the Nexus 7, suggest the killer app for small tablets: the virtual assistant. They're both so fast, accurate and uncannily insightful that people will want to to use them all day, every day.

Eventually, I believe, virtual assistants on both iOS and Android tablets will be given the power to control apps on the device. That combination will transform small tablets and phones into Star Trek computers that answer questions and go off and do things in the world on behalf of the user.

Small tablets are also perfect social networking machines. Phones are popular devices for interacting on , but not because it's a compelling size. Phones are way to small for the visual, photo-centric way people do social networking. iPad sized tablets are also flawed, because they're less mobile. But 7-inch touch tablets are an ideal combination of big screen and mobility. 's new on Nexus 7 is by far the best social networking platform ever introduced. and Twitter will probably follow with similarly great tablet-specific apps.

So while the larger iPad-size tablets are slightly more usable from a user interface perspective, smaller tablets are vastly more usable from a location and circumstance perspective.