Some info on the Main Players, page-30

>Perhaps just cheaper to launch?

At a guess low earth orbit -> rapid rate of decay -> lots of cheap disposable satellites. low orbit may give lower transmission power, But probably also requires some form of relay between satellites to see a ground station.

I've got doubts the surface area of solar cells on the nano size would give enough power for an onboard computer and transmission power of a cell phone. But I haven't run the numbers to confirm.