The official rollout on Tuesday of IBM’s Lotus Symphony suite of productivity applications along with the launch yesterday of the official beta version of Acrobat.com from Adobe has all the experts asking the same well-worn questions: Now that Adobe, IBM, and Google all have skin in this game, is Microsoft Office under siege yet? And which online offering comes closest to being a viable alternative?

IBM’s solution, available for about six months in beta, is free, at least for the basic applications, and offers a great deal of collaborative features. But while it is a product you download from the cloud, it is not cloud computing.

“Symphony sits on the transition between two worlds of on premise and online,” says Doug Heintzman, director of strategy for IBM collaboration.

Heintzman claims Symphony has all the attributes of an on-premise application in terms of UI attributes, responsiveness, and performance, along with large dictionaries and the ability to easily work offline or on.

The collaborative part comes from the fact that it is built on open source Eclipse technology, which will allow millions of users to add widgets and plug-ins to the basic set of applications. Heintzman says that is already happening across the Web.

While Symphony 1.0 may not appeal to the hard-core productivity application user, says Jim Murphy, director of research for document management at AMR Research, the set of open APIs that comes with Symphony will allow the casual business user who just wants to put notes in a database rather than opening another application to have the word processor pop up in their current application.

“There is a lot of emphasis [from IBM] on the APIs and its integradability,” says Murphy. 

Melissa Webster, a senior analyst with IDC, believes Symphony represents IBM’s relentless assault on one of Microsoft’s two core franchises: productivity applications.

And IBM is doing it in a way that not many other companies can duplicate: through its huge support capabilities. IBM is underwriting support by offering annual support for $25,000 covering 20,000 desktops -- relatively inexpensive for the enterprise.

“It is very inexpensive, and it removes any inhibitions that are support related,” says Webster. 

When asked if he thinks Symphony is an “Office killer,” IBM’s Heintzman puts it in a larger competitive context.

 “An enormous amount of revenue is captured in this space by Microsoft,” says Heintzman. “This means at this moment they control the space by the network effect that drives their monopoly.” Heintzman says IBM has an interest in changing the landscape of the marketplace.

Asked if he thought other Office competitors such as Adobe.com, ZoHo, and Google Apps might be considered allies in this fight rather than competitors, Heintzman agrees: “We applaud and support [Adobe] BuzzWord and what Google is doing.”

What also makes IBM’s efforts a bit different than Adobe’s and other competitors to Office is the fact that from a business perspective, IBM does not need to use Symphony as a revenue stream.