Ten years ago, Sabeer Bhatia co-founded Hotmail and sold it to Microsoft for just under $400 million. Now he's launching a Flex based competitor to Microsoft Office called Live Documents. So far the site isn't allowing registration, although you can sign up for an invite as everyone else has. It does sound interesting - plugins into the Microsoft Office applications allow you to enable them to work with Live Documents, and what sounds like a browser based interface (though possibly leveraging Adobe AIR as well) allows you to collaborate and work on your documents from anywhere.

There's lots of commentary on the web about this. I think Matt Asay from CNET had the original story, and then posted an upbeat update to his original story a day later, after receiving more information. Slashdot has the story, ZDNet's Between the Lines blog chimes in with some commentary, and Ryan Stewart has a post on it as well.