I have been reading with some interest in using the Google Earth API to view public data in your average browser. 3D is available using the center mouse button but I really do miss the Google Earth navigation tool they got rid of in the old version for tilting. The new one just is not as intuitive (or useful, in my opinion). 4D, or time slider inclusion, is still a feature request for the API at this time.
I have been most impressed with the Peachtree City Google Earth Map (Beta) as well as New Mexico dreaming sites.
These sites are interesting examples of how to use the API to promote spatial awareness in terms of municipal functions and infrastructure planning, not to mention emergency preparation and so forth.
I have posted all of my commercial real estate brokerage's land ownership research data into a webpage that my coworkers can use to access internal data with relative ease compared to, for example, an ArcIMS site. Granted, ArcIMS sites can offer much more in terms of analysis tools available. It does seem, however, that most casual users of mapping technology spend the majority of their time panning, zooming, and identifying items within the map than they do performing complex GIS analysis. And the price difference for ArcIMS ($$$) vs the Google Earth API ($0) is difficult to to avoid.
Here is a link to an example I have recently dabbled with. It features the city lots of Steamboat Springs, CO, along with some extra data such as land zoning, EMS response zones, and so forth. I have not yet made the parcel numbers searchable like the Peachtree City site, but I anticipate adding more data and functionality to it in the future.
Would any municipality be interested in someone (perhaps me!) setting something up like this for their constituents?
Steamboat Springs Google Earth API