Hotmail co-founder Sabeer Bhatia is placing his bets on an online office productivity suite that aims to compete with similar offerings from Microsoft and Google.

Instant Collaboration Software Technologies Pvt. Ltd (InstaColl), a Bangalore company co-founded by Bhatia, unveiled Live Documents on Wednesday, an online service that allows users to access and edit documents using a browser, and collaborate on and share documents with others.

The service works with any browser that supports Adobe Flash and runs on any operating system, Sumanth Raghavendra, chief executive officer of InstaColl, said on Wednesday.

Online documents can also be worked with off-line, using an optional desktop client application that "wraps around" Microsoft Office to give it online collaboration capabilities, Raghavendra said. Users can work on a document in Office when off-line, and the document will be updated in Live Documents the next time the user goes online, the company said.

The hosted service, which is available as a limited technology preview at www.live-documents.com, will be free for individuals to use, but corporate users will have to pay. Corporate users can sign up for the hosted service or buy a license to run the software on a server at their own premises, Raghavendra said.

Live Documents uses Adobes' Flash and Flex technologies. Raghavendra argued that this gives users a better experience than Google's hosted applications, which he derided as a stripped-down version of Microsoft Office.

"Even power-users of Microsoft Office can use our service," he said. Microsoft will not sacrifice its packaged desktop software business by offering a full online productivity suite, he said, which creates an opportunity for companies like InstaColl.

Bhatia, who shot to prominence after selling Hotmail to Microsoft for a reported $400 million in 1997, told reporters in Bangalore that the new application addresses a bigger market opportunity than Hotmail.

InstaColl is targeting both the office productivity market, which it estimates to be $20 billion this year, and the market for document management and collaboration software.

The decision to offer the service free for personal use was prompted by the need to popularize it, Raghavendra said.

The application currently supports Microsoft Office on the desktop for users who want to work off-line, but will also support OpenOffice.org, an open-source office suite, in a few months. InstaColl also plans to launch by that time its own desktop client for working off-line.