Microsoft Office applications will be among the many services Facebook users will be able to access directly from the social networking site's beefed up new messaging system, which was unveiled Monday in San Francisco by Facebook CEO Mark Zuckerberg.

Facebook Messages users will have two ways to send and receive Office files created in Word, Excel, or PowerPoint to friends and colleagues.

They can upload and download documents authored in the desktop versions of the software, or simply include an "attachment" that gives the recipients access to a document created in Office Live, Microsoft's cloud-based version of the suite.

"Inspiration and the need to share documents can strike at any time and in any context – yes, even while looking at pictures of a friend’s new pug on Facebook," Microsoft officials noted, in a blog post on the new service.

"You may want to send your friend a spreadsheet containing data you pulled together on organic dog food prices in shops within the Bay area. Lucky you…Microsoft Office is now a part of Facebook’s new messaging system, allowing people to view Word, Excel and PowerPoint attachments with the Office Web Apps directly in Facebook," Microsoft said.

"If you have Office installed on your computer, you will be able to download, edit and save attachments to your computer," Microsoft said.

The integration of Facebook Messages and Microsoft Office may be a sign the two companies plan to work together more closely in an effort to fend off Google, which earlier this month shielded its APIs from Facebook and is rumored to be eyeing its own social networking service.

While Facebook Messages may cannibalize Microsoft's Hotmail user base to some extent, the free Hotmail service is hardly a cash cow for Microsoft. Also, Facebook Messages—for now at least—does not appear to be sufficiently robust to pose a threat to Outlook's market share. It's more a challenge to Web-based e-mail services like Google's Gmail.

Even though Facebook said its new Messages system isn't e-mail per se, it will provide a free, @facebook.com address to all users who request one.

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