Hmmm, I dunno what AT&T classifies them as internally, you may well be right, but to the user, they're functioning as an MVNO. They're selling AT&T service on the Kindle. M2M in my eyes is more like, say, a device to track a truck driver, or an alarm system - things with no user interaction. Not a device you use to browse the web and buy content on. But yes, I could see AT&T etc classifying it as M2M use, which is probably how Amazon can afford to offer it.