Microsoft's SaaS boom
"Microsoft has invested heavily in making many of the productivity features available in the Microsoft Office and Outlook available in its SaaS versions of the software."
This hits the nail right on the head. Office 365 will drive Microsoft's SaaS growth for the next few years at least. This isn't necessarily because the software solution is so great that people will migrate in droves, it is a mixture of several things. First yes, the flexibility of O365 and features that work best in 0365 will draw some people in. It isn't quite seamless now but the Office apps tying to OneDrive and SharePoint has matured greatly and can streamline a lot of little tasks. Secondly is the natural path of the software lifecycle, eventually O365 will be adopted by most companies because it is the next version of Office without consideration to much else. Lastly is the Enterprise Agreement changes, smaller companies are being locked out of the old licensing model after this year, agreements are getting pushed toward the new licensing model that makes O365 pricing much more attractive than doing everything on premises. As those old agreements run out I suspect we'll see the bulk of small and medium businesses move toward Office as a service.