Here is an introductory article to OpenStreetMap (OSM) . A short except :
Why is that important? Because each time you fix something in OSM your brain gives you a little drop of seratonin, or something, that makes you feel good. And that comes from a quick feedback loop. With traditional companies your feedback loop is far, far too long. Anything more than a couple of minutes is too long because there’s no association of the act of fixing something with the good feeling. More often than not, you help fix something and it drops in to a black hole.
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The logistical costs of producing maps in a top-down fashion pretty much levelled out at having fleets of cars driving around North America and Europe. Increasing the detail with footpaths would cost far more than the benefit any company could leverage if they tried to do it a similar way. Crowd sourcing this from customers and others is simply inevitable – there is no other way to do it. But many will likely try to add quality assurance in between their contributors and the map and thus limit the scope and depth of the contributions.
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Those maps will, at times and in certain areas, be better than OSM. But the growth of OSM is inexorable and like a freight train will ultimately roll over everything in its path. It may even happen before traditional companies figure this out and try to start seriously crowd sourcing data.
Is OSM the next wikipedia of mapping data ?