Microsoft is optimizing its upcoming Office Web Apps for .docx, .pptx, and .xslx, which will boost the online accessibility of documents uploaded from users’ desktops—but in the process, perhaps making life more difficult for those using older versions of Office. During testing of the Web Apps technical preview, eWEEK found that documents with .xls and .ppt file extensions could not be edited through the browser, although they could still be viewed and downloaded.

Office Web Apps will be available to subscribers of Windows Live. Nick Simons, Microsoft’s program manager of Office Web Apps, wrote in an Office Web Apps blog posting on Oct. 20 that the program’s technical preview had been expanded for "a limited time" to a larger pool of users.

Microsoft first launched its limited technical preview of Office Web Apps on Sept. 17. With the full version due for release in the first half of 2010, the preview provided a very limited degree of functionality: users could view documents with the Word Web App, view and edit documents with the PowerPoint Web App and Excel Web App. Microsoft executives told eWEEK during the preview launch that a OneNote Web App would be added at a later date, once certain development milestones were reached.

During testing of the technical preview, the results of which can be found in two posts on the Microsoft Watch blog here and here, eWEEK found that much of the Web Apps’ functionality worked as promised. However, Web Apps displayed error messages whenever an attempt was made to online-edit PowerPoint documents with a .ppt file extension, or Excel spreadsheets with an .xls file extension.   

By contrast, uploaded files with .pptx and .xslx extensions could be edited online with no issues.

"Office Web Apps support documents created in Office 2003 and later," a Microsoft spokesperson told eWEEK when asked about the issue. "However, we optimized for editing and saving .docx, .pptx, .xslx formats because of the important features in Open X M L that support long-term document retention, preservation and accessibility, and the overall read/write performance the file format offers."

While a large number of Microsoft users rely on Office 2003 or later versions for their productivity needs, a subset that utilizes older software may be limited in their use of Web Apps, at least in the technical preview. A recent report by research firm Gartner found that 80 percent of commercial machines still run Windows XP, while a separate research note by Deutsche Bank found that the average age of an enterprise PC had reached 6.1 years by 2008.  

The full beta version of Web Apps will be released before the end of 2009, according to Microsoft. Despite that limited functionality, the technical preview offers an idea of how Microsoft is proceeding into the cloud-based productivity space, an arena already occupied most notably by Google Apps and other free applications.

By offering a stripped-down, browser-accessible version of its Office applications, Microsoft evidently hopes that it can seize market-share in the growing cloud-productivity market. Office Web Apps will support browsers including Internet Explorer, Safari and Firefox; in addition, multiple users will simultaneously have the ability to edit Excel Web App or OneNote Web App documents from within the browser, and then publish Excel data or PowerPoint presentations to third-party Web sites, blogs or wikis—with embedded information within those documents automatically updated whenever a change is made. 

Despite this functionality, and a standard-issue toolbar inserted into Web Apps in order to give it a desktop Office feel, Microsoft will not include certain features in the online version that will be available in the full Office 2010. When Microsoft releases Office 2010 next year, it will offer the productivity suite as both a hosted subscription service and as an on-premises application.