Estimates from Google say that there are over fifty thousand different applications on the web that are making use of Google Maps. This feature brings Google Maps more in line with Google's standalone program Google Earth, which also allows overlays to be used in its interface.
Known in Google Maps communities as 'mashups', Google will encourage developers to use Google tools to create small applications termed 'mapplets' and post these mapplets under the "My Maps" section of Google Maps. The My Maps area of the site can then be accessed by anybody with a Google account.
Most mapplets are created by Google itself, but the number of mapplets is expected to grow massively in the coming days and weeks. There is a 'Distance Measurement Tool', which can be used to measure the length of real structures. For instance, the image below show the length of Waverly Bridge in Edinburgh - 215.05m. This is overlaid with the "Photos from Panoramio" mapplet, which allows users to see pictures taken by people in specific places all over the world.
An example of the power of mapplets is the combination of the "Gas Prices" mapplet and the Traffic service provided by Google - you could work out the most frugal place to buy your cheap petrol while avoiding traffic jams and therefore saving the petrol you already have. Another example would be searching for houses in certain areas of a city, where you could see the houses marked on the map along with local crime rates or school locations.
The opportunity for businesses to take advantage of the service is also massive - for instance, allowing a mapplet to be activated to show where every McDonald's restaurant in the world is located.
Google's Director of Maps, John Hanke, summed up the service well when he said: "It's like combining chocolate and peanut butter. They're good by themselves, but the combination is much more valuable than when they are served in isolation."
