I'm not sure if this is a widespread problem, but just in case — if you live within any of those gaping white spots in the image above, you probably shouldn't waste your money on the Kindle. Keep in mind that Amazon's wireless connectivity for the device is dependent on the Sprint network and, as everyone knows, Sprint's network blows goats in rural areas.
As a rightfully irritated commenter on BookofJoe noted, Amazon should have notified him of this when it bought it. That may be true, but you wouldn't expect your phone company to do that right? Besides, Amazon did mention all of this in the product page, but it could have been easily lost in the long list of information. Hit the link to check your coverage [Amazon and BookofJoe]