I'll add to what @harel says below. If it wasn't for MongoDB, my last company would have probably not survived. Sure, our usecase was very specific (very write-heavy app) but MongoDB delivered and still delivers without any problems. I think there can be usecases where MongoDB is not the best fit, but for wide number of applications, MongoDB is the perfect fit.
Outlook is the most used enterprise application used written by Microsoft. Azure could potentially be the next Outlook, in terms of adoption and usage (and could be the next cash cow for MS).
I want to clarify (and I have edited the post some) that this is all a forward-looking article. I am not saying that the WebPI is already working with Azure; but that knowing how Microsoft is a technology-leveler of sorts (specially for the enterprise) I could see the WebPI evolving into a point-and-click app installer once Azure is deployed, allowing developers to write packages that are cloud-aware to be listed on the apps gallery.