At the Opening Session at the Realcomm two different ways of data gathering was displayed.
John Hanke, general manager of Google Earth (an founder of Keyhole), did a great presentation of Google Earth which included a display of Bombay city with all major buildings named out on the map (se below). The interesting part is that this informed has been put in place by the users 'the Google community. In other words, collaborative information gathering. Something that John was pushing to the real estate audience; "why not put in information about your buildings in the system and market it to the 100 million users?".
In contrast to the approach of having the users themselves putting in the data CoStar's founder and CEO Andrew Florance ran through their new retail solution.
Also that an impressive product, but you have to wonder, what if Google manager to have the industry to put in the same data into Google Earth for free?