I've heard this question a lot when people ask me about what Yahoo are going to be offering in the cloud. A lot of people don't understand the difference betwe

I've heard this question a lot when people ask me about what Yahoo are going to be offering in the cloud. A lot of people don't understand the difference between Amazon's and Google/Microsoft's approach to cloud offerings. Amazon seem to be providing a lot of infrastructure pieces, from virtulization to storage and CDN to RDMS. However how you connect those pieces or which you use it's pretty much up to you. Google on the other (and Microsoft judging by the current descriptions of Azure) have provided a platform which guides developers towards good practices with constraints but is more limited in the possible applications. That said they won't make your application performs, they'll just make sure it fits in their scalable architecture. So the short answer is yes. You can build a truly scalable application on any or all of these cloud services if you know how. If you know how, though, you can probably do it without them.