OMB's Peter Orszag blogs on why Data.gov matters:

Data.gov will...help government agencies -- so that taxpayer dollars get spent more wisely and efficiently. Through live data feeds, agencies will have the ability to easily access data both internally and externally from other agencies, which will allow them to maintain higher levels of performance. In the months and years ahead, our goal is to continuously improve and update Data.gov with a wide variety of available datasets and easy-to-use tools based on public feedback and as we modernize legacy systems over time.

Democratizing government data will help change how government operates -- and give citizens the ability to participate in making government services more effective, accessible, and transparent

Orszag is making a case that fits right into the Nudge-style behavioral economics argument that is popular in DC at the moment. (Nudge co-author Cass Sunstein has, you might know, been nominated to head the office that oversees how federal agencies and departments make regulations.) Here, what's being nudged is government itself.

We talk a lot about how standardizing and publishing government data will encourage citizens to remix and rework information to meet their needs. But Orszag, in his own understated blog style, is making the case that just as important is how creating an expectation of standardized government data through Data.gov will create a feedback loop of accountability within government.

There's a competitive aspect to this approach to government data. Similarly, you might look at the White House's new Innovations Gallery, launched yesterday. The site showcases the best use of online interaction across the government web. One audience is no doubt the public. But it's fair to also see it as an attempt to create a healthy sense of competition between government entities to see who can take the lead in the contest to best tackle Web 2.0.