One of the many areas where Google is far ahead of Microsoft is mapping, with Google Maps by far the dominant map service on the Internet. Microsoft is employing an under-the-radar approach to fighting back, lending big support and big dollars to the open source map project OpenStreetMap. It looks as if the tactic is starting to pay off.

OpenStreetMap is run much like Wikipedia, in which volunteers provide mapping information to build a free, open mapping service. People, sites, and companies can then use that mapping information. The services is overseen by the non-profit OpenStreetMap Foundation. The foundation says that a half a million volunteers have already provided data to OpenStreetMap.

The New York Times reported recently that a variety of companies have started to defect from using Google Maps because of the high fees charged for the service, and instead have turned to getting mapping data for free from OpenStreetMap. The mobile social media service FourSquare has jumped ship, and for iPhoto, the iOS photo management app, Apple has switched from Google to OpenStreetMap.

Behind the scenes, spurring all this on, is Microsoft. Microsoft hired OpenStreetMap founder Steve Coast to work for Bing as Principal Architect for Bing Mobile. Coast works on both Bing and OpenStreetMap. In a blog post announcing Coast's hiring back in November 2010, Microsoft said Coast will "develop better mapping experiences for our customers and partners, and lead efforts to engage with OpenStreetMap and other open source and open data projects."

The Times reports that Coast is working on developing open-source software that will make it simpler for developers to get data from and use OpenStreetMap. And it also reports that Microsoft has been donating "valuable map data" to OpenStreetMap. Bing also uses OpenStreetMap data for its mapping service.

Any OpenStreetMap success eats into Google's mapping dominance and bottom line. Given the tight connections between OpenStreetMap and Bing, it also helps Microsoft. At the moment, Google Maps remains dominant; the Times says that 71 percent of the nearly 92 million people who viewed a map online in February were using Google Maps.

Still as the defections from FourSquare, Apple, and many smaller companies show, OpenStreetMap is starting to have some effect on Google Maps. Microsoft's embrace of open source mapping seems to be starting to work.

This story, "Microsoft's Secret Weapon Against Google Maps -- Open Source" was originally published by Computerworld .