Infinite Apple posted screenshots of what writer Paul Paliath believes are evidence that Apple iCloud is using Microsoft Windows Azure and Amazon Web Services to store content. GigaOM ran an article after consulting three networking and cloud computing experts who concluded that the data Paliath posted wasn't sufficient to prove that iCloud was using AWS or Azure.Last week
The dump file Paliath posted indicates that an image sent through iMessage passes through Microsoft's Binary Large Object (BLOB) Service. Paliath speculates that Apple doesn't actually host the iCloud content, but instead manages links to content.
It could be that Apple's new data centers in North Carolina isn't fully operational yet that Apple is taking advantage of AWS and Azure for the time being. Perhaps this is only temporary.
Also, as GigaOM has explained Apple will clearly still being hosting some content, particularly music.
Another possibility is that Apple is simply using AWS and Azure as a CDN. In this scenario Apple would host the content and caches would be stored on other servers to provide faster access. According to GigaOM, Apple has typically used Akamai and Limelight as CDNs in the past. However, it's not clear whether Microsoft offers an Azure CDN service for content not hosted in Azure. See this MSDN article for more information about how Azure CDN works.
ZDNet's Microsoft maven Mary Jo Foley contacted Microsoft for comment, but the company told her that it does not release names of customers. Apple did not respond to her request for comment.