CIO — Like a lot of Google announcements involving software, it happened very quietly.

Sometime during the past few days (some news reports say over the weekend), the Internet giant began offering Sun’s StarOffice (normally $70) for free with its Google Pack software bundle, giving users the chance to create documents with something other than Microsoft Office applications while also insulating them from any potential legal tangles that could encumber the purely open-source Open Office suite of productivity tools.

Until now, the most common problem cited with the Web-based Google Docs & Spreadsheets is that it doesn’t offer the rich features available on a Microsoft Word or Excel class of desktop application.

To this point, Google has never been overly concerned with what tools people use to author documents because Google Apps’ primary advantage rests in its collaboration potential. “We’ve focused a lot of attention on letting people compose their documents any way they want,” Rajen Sheth, the product lead for Google Apps, told CIO in a phone briefing. “What we’re trying to do is build applications that make it easier for people to collaborate and use the fact it’s on the Web and connected to do so.”

By offering StarOffice, however, Google now gives its users a more feature-rich—while still free—option for authoring documents before they import them (or even copy and paste) into Google Docs & Spreadsheets.

“The Sun software shores up Google’s productivity software until they can really expand the capability of their own software and allow it to be run offline,” says Michael Silver, a Gartner analyst. “It’s a short- to medium-term solution,” he adds. “Making Google Apps more robust is not an overnight thing, but Google already has and will add additional features over time.”

This move builds on the initial 2005 agreement between Sun and Google, which added the Google toolbar to some Sun products. The extent of the deal, however, was unclear at the time, though it left the door open for further collaboration on projects such as Open Office. The difference between Sun Office and Open Office is rather small. Each has a different spellchecker, and Sun Office offers some additional templates and slightly more beefed-up features than its open-source sister.

Google may have opted to offer StarOffice to give the company and users of Google Pack, certain legal protections, too. “Using the Sun code, rather than vanilla OpenOffice code, insulates them and their users from any lawsuits that Microsoft may eventually decide they want to bring,” says Silver. The 2004 settlement between Microsoft and Sun provided protection from Microsoft lawsuits against StarOffice as well as other Sun products.

Microsoft has not publicly said if it will pursue legal action in the future over Open Office but left the option open in a patent agreement with Novell that both companies hoped would spur better interoperability between Windows and Linux. In the patent filing, Microsoft made mention of “clone products” but didn’t mention specifically if it believed OpenOffice to be one.