Unlike rivals like Google or Zoho, Microsoft is betting on an online shared workplace to work in tandem with its desktop based applications.
It is currently testing Office Live Workspace at Officelive.com; the site is not available for users outside US it seems and you will be redirected to the UK webpage for Office Live Small Business (opens in new tab).
Unlike the latter, Workspace will allow files to be shared online seamlessly, something that Google Docs has nicely managed to do for more than one year now.
The initial offering will include 500MB of free storage and will be compatible with Office XP, 2003 and 2007; ZDnet (opens in new tab) confirms that you need not be an Office user in order to open an account on Office Live Workspace.
It has also been confirmed that Microsoft is planning to serve adverts on OLW and hasn't announced an ad-free paid for option.
That said, Microsoft is giving away two online applications - web notes (opens in new tab) and something akin of a mini list maker/spreadsheet. But don't expect Microsoft to release anything remotely close to Microsoft Office.
The company cannot afford to touch its cash cow although it has been rumoured to be preparing an ad-supported version of Microsoft Works... just in case.