Forbes offers an overview of applications that can work on a municipal network: The three examples cited at the outset of the article are all from the briefing book of Motorola's mesh division (developed through the Mesh Networks acquisition). I particularly like the pothole example. Many cities have found that efficient pothole dispatching keeps citizens thinking their government works!
It goes far beyond governmental use, of course, into tracking lost Alzheimer's patients and creating citywide networks for meeting others. The applications of a single, seamless (or nearly so) ubiquitous Wi-Fi network should go far beyond mere Internet access, but this is the first overview of this larger purpose I've read.
Cell companies used to have the handle on this, but their application focus these days seems to be on delivering media in the U.S.; in Europe and Asia, there's much more of a focus on community building to increase phone usage.