Tim O'Reilly is enthusiastic, and rightly so, about the promise of innovation in "Government 2.0," the concept of government serving as a platform from which new services and applications are made available to the public. So, if the government is a platform, how do businesses and other developers build on it?In a recent column, O'Reilly, the Web 2.0 evangelist, offers the iPhone ecosystem as an example of the platform dynamic he has in mind, with a thriving community of developers writing thousands of innovative new applications.

Of course, the U.S. government is unique in many ways, making it difficult if not impossible to find a platform ecosystem that serves as a good point of comparison for how government as a platform might work. Considering the size and scope of the U.S. government, the legacy systems and processes in place, and the need to balance national security and individual privacy with openness, we're learning as we go.

Wikis, blogs, Twitter, and other social media are part of the answer, but there's much more to it. I talked to O'Reilly about what's needed for Government 2.0, and he laid out some of attributes of good technology platforms that could carry over to government. They're "open ended, not fully specified in advance, modular, extensible, and simple," he says.

I would add that government-as-platform should include open source, APIs, database access, and cloud computing. The Defense Information Systems Agency, for example, recently announced that it was releasing an internally developed stack of Web apps as open source. DISA's Forge.mil open source portal is another step in this direction. A government-wide open source portal along the lines of SourceForge could be (should be?) next.

The feds are making data available in a variety of formats for download and reuse, with Data.gov's data catalog and the IT Dashboard's data feeds as examples. A next step would be to open more data from more sources, with APIs and associated tools to support communities of developers, along the lines of what eBay and Amazon have done for their ecosystems. In fact, the most sought after items on the Sunlight Foundation's's open government wish list are APIs and bulk data access.

Government 2.0, O'Reilly says, is a chance to "redefine the public-private partnership." Note that NASA and Google recently partnered to make high-res images and video of the Moon's surface available on Google Earth. It's one small example of the kind of innovation that becomes increasingly feasible as the government platform opens up.

The challenges of Government 2.0 -- privacy, security, bureaucracy, regulation, data silos -- are as formidable as the opportunities are plentiful, and, in many cases, have a technical component to them. O'Reilly points to government procurement as one the major hurdles ahead. Just as APIs and source code are part of the platform, process and policy must be, too.

The Government 2.0 platform is taking shape now, and in many respects the path ahead and the outcomes are yet to be determined. O'Reilly says this is a huge opportunity for the technology community -- entrepreneurs, tech vendors, and business IT departments alike -- to engage Washington in how things play out. One way to do that is to attend the Gov 2.0 Summit and the related Gov 2.0 Expo Showcase, which take place Sept. 8 - 10 in Washington. The events are co-sponsored by O'Reilly Media and TechWeb, which publishes InformationWeek. I'll be there along with several of my colleagues. Watch this blog and our IW Gov Twitter feed for updates from the events.