That's not all-- it's also a divide of knowledge and interest in digital technology. Particularly, the kind of technical knowledge and interest that allows people to innovate and build on these platforms (as opposed to just turning into consumers).
This is where I think the difference between Desktops and Mobile devices stands out on this subject-- Desktops are way more tinkerable and teacher-friendly. I can show someone hands-on how the hardware and software of a desktop computer work together much easier than I could on a mobile device (where are the form factors and modularity?). And I think that makes a big difference in terms of getting people interested in _building_ versus consuming.
So as the gap of Internet access narrows in some communities, I see more people embracing tech as consumers and less people understanding or learning about it. Mobile penetration figures are a little misleading because it's not marking close of the Digital Divide as much as just making it look a little different.
While I think mobile devices are an excellent way to get previously-unconnected people on the Internet, access is just one of many issues that make up the Digital Divide. In many ways, its an issue of future socioeconomic progress moreso than an issue of getting more people online.