But Adobe Acrobat.com and Lotus Symphony do add to the growing list of products, both hosted and on-premise, aiming to chip away at the Microsoft Office software suite's dominance in the desktop applications market.
"It's very clear that the Microsoft Office franchise is under assault, and it's under assault in innovative ways," said expert Bernard Golden, CEO of Navica in San Carlos, Calif.
Acrobat.com, launched Monday, is a free hosted suite that includes word processing, Web conferencing, file sharing, PDF conversion and APIs for developers. Lotus Symphony, released Tuesday, is a free software suite based on the Open Document Format (ODF) that features word processing, spreadsheets and presentations. Other Microsoft Office competitors include OpenOffice, Sun's StarOffice and Google Apps.
The unique features of Adobe Acrobat.com could help it get traction in the market, but IBM Lotus Symphony is probably too similar to OpenOffice to have much success, Golden said.
"The Symphony stuff is kind of a 'me too,' and it's a little bit late to the party," he said. "I'm not sure there's a lot of people looking to adopt that product."
Any of these alternatives will have a hard time competing for existing users of the Microsoft Office software suite, said Dave Sobel, CEO of Microsoft partner Evolve Technologies in Fairfax, Va.
"I don't see many existing customers throwing away their investment in Office," he said.
Adobe Acrobat.com, Lotus Symphony and others may have more success competing for new customers, especially as younger entrepreneurs start businesses and realize they don't have to pay for desktop applications, Sobel said. That's one reason these new releases will have better luck than past Microsoft Office rivals, Golden said.
"They're free, and I'm a huge believer in free as an enticing value proposition," he said.
Being open, like Lotus Symphony, or available online, like Acrobat.com, also help these products differentiate themselves from the Microsoft Office software suite. It's harder for Microsoft to respond to that kind of competition, Golden said.
"Before, they could just say, 'Do you want the real thing or the pale imitation?'" he said.
Adobe Acrobat.com and Lotus Symphony are still playing catch-up, but the Google Apps business model -- providing a free service that generates advertising revenue -- is doing well, said Michael Healey, chief technology officer for GreenPages Technology Solutions, a Microsoft partner in Kittery, Maine.
"None of these programs have compelling revenue models for the channel, but I don't think that's too big of a deal anyway," he said via email. "Microsoft Office license sales have become a commodity buy -- if you are a straight procurement shop, this trend is a major threat."
Rand Morimoto, president and chief operating officer for Microsoft partner Convergent Computing in Oakland, Calif., said Microsoft needs time to shift from the on-premise software market it has controlled to this new online services world. Then the company will be better equipped to respond to the threats posed by Google Apps.
"A company as big as Microsoft can't jump into the online market immediately," Morimoto said.
In the meantime, he said he expects Office's standing in the market to stay strong.
"People are familiar with it," he said. "It works extremely well. Microsoft has invested in it to make it even better than before."