For me personally, I'd largely agree with your first definition - but I would expand it to services run on "private clouds" (ie, a corporate having a couple hun

For me personally, I'd largely agree with your first definition - but I would expand it to services run on "private clouds" (ie, a corporate having a couple hundred virtual machines on a rack full of blades I would consider "cloud based"). However, if I look at our customers (techies and enthusiasts who build their own computers), they define a cloud based service as anything primarily online - IE, your second definition. I think this definition is gaining ground.