When one thinks of software-as-a-service, you're likely to think of enterprise-type applications, like customer-relationship management (CRM) or human resource software. However, it is in the environment of personal productivity software, like word processing and spreadsheet applications, where the real cloud computing battles are likely to be fought (and won).

That enterprise focus can be seen in a recent InformationWeek Analytics 2010 survey, in which the highest percentage of software-as-a-service users (41%) cited Salesforce.com as their SaaS vendor of choice, followed by Google (28%) and then a tie between Microsoft and Oracle (26%).

In terms of desktop SaaS, Google's online personal productivity software, Google Apps, jumped out to a mindshare lead, while Microsoft has had great success with online versions of its SharePoint and Exchange collaboration and e-mail software. Microsoft is countering Google's desktop SaaS effort with Office 2010, released this month.

Software-as-a-service, and by extension cloud computing in general, is a bottom-up phenomenon, empowering end users in the spirit of the "consumerization of IT." And that dynamic is finding its way to the desktop, where users are experimenting with the best combination of online and on-premise capabilities.

That's why Microsoft is doing a smart thing by tying its online app capability to its corporate-standard Microsoft Office application suite. In his review for InformationWeek of Office 2010 and its Web components, writer Ivan Schneider offered this: "In combination with other features of Office 2010, however, these humble Web services may help Microsoft turn the tables on its upstart online challengers, regaining its once-dominant prominence in 21st century computing."

(Here is an image gallery of Microsoft's Office 2010 Web apps.)When one thinks of software-as-a-service, you're likely to think of enterprise-type applications, like customer-relationship management (CRM) or human resource software. However, it is in the environment of personal productivity software, like word processing and spreadsheet applications, where the real cloud computing battles are likely to be fought (and won).