Microsoft unveiled its newest version of Office Wednesday, at a time when one of its biggest revenue drivers is feeling the heat from rivals.

The rise of free, Web-based applications like Google Docs, and the growing popularity of other open-source office suites like Oracle’s Open Office has put pressure on Microsoft.

Gone are the days when Microsoft could simply unveil a new version and know the market would rush to adopt it.

Microsoft also didn’t really help its cause with Office 2007, the most recent version. Office 2007 has been compared by many analysts with the universally panned Windows Vista for overcomplicating functions and getting rid of some of the most familiar features of earlier Office iterations.

In response, the company has come out swinging. Office 2010 is a vast improvement over its predecessor. It comes with many updated and revamped functions as well as the ability to access Office online for free.

That’s welcome news for the 500 million Office users worldwide. It’s also good news for Microsoft, since nearly a third of the company’s revenue comes from the Word, Excel, Powerpoint and Outlook suite.

(Read More: CNN Money)