The advantage to this strategy is that it helps Google add features to Google Apps that its developer and engineering teams, which focus on core functions of the software, might not otherwise have time to create. An example of this occurred recently with Google Spreadsheets.

Sheth and his Google Apps project team focus primarily on what he calls the 80 percent use case — meaning, he wants to build the application so that for 80 percent of users at a company, it has all the features they would need. So when people complained the Spreadsheets didn't have a pivot table capability, he let the openness of the Google Apps platform do its work.

"Pivot tables is kind of a power-user functionality, so it's not something we'd go to as the first thing we'd build," Sheth says. "But now we have a pivot table that was actually built by a third party that extends the functionality of spreadsheets."

The third-party was a vendor called Panorama, which focuses on Business Intelligence (BI) software. It used Google Gadgets, which allows people to build or place applications on top of Google Spreadsheets. By tapping the abilities of third-party developers, analysts say Google can keep the product innovative and less static.

According to the Yankee Group analyst Edwards, Google's ability to build a developer community could help them like it did for Microsoft years ago in creating an ecosystem of developers around Windows. Last week, Google held a conference in San Francisco and outlined its plans for investing in third-party developers. "If you get a developer community behind you, you can get new and innovative stuff daily," Edwards says.

Part of this picture also includes, for Google, the fact that Google Apps makes no presumption that it is your only enterprise vendor, says Sheth.

They have built tight integration with existing e-mail and calendaring systems such as Outlook and Exchange and will continue to hook into more systems moving forward. Google Docs & Spreadsheets can import and export files to PDF, Office files, or openoffice.

"One of the core philosophies we want to push is that we don't assume we're the only thing out there," Sheth says. "These applications are built to assume that they'll work with apps customers already have, both in the cloud, and on premise."

It's Social

Traditional e-mail and productivity tools for businesses have typically been anti-social. For instance, if a user composed a document on Microsoft Word, the ability to share it with colleagues in real-time has been fairly limited. At most organizations, the tendency would be to e-mail it around to coworkers, or, if the company used Microsoft SharePoint or Office Live, they could check it in and out of a central repository.