"Orkut was global, and in a global context, mobile devices may be more heavily used than laptop / desktop web."

Mobile devices have web browsers. In fact, by some measure, the ability to run a web browser would be the defining characteristic of a "smart" phone.

We had a name for phones that just ran little applets - they were called "feature phones". Some of them had very interesting, even great features.

But it's the browser, and things like the browser, that make the smartphone smart.