This insightful post by StephaneP attempts to shine some light on the complex world of coordinate accuracy. In short — due to the movement of tectonic plates — WGS84 coordinates can’t be accurate unless you know the time that the coordinates were captured. He also considers the impact this has for OpenStreetMap and what could be done to improve coordinate accuracy on the platform.

StephaneP’s diary | You thought OpenStreetMap data uses the WGS84 datum? No it doesn’t! | OpenStreetMap
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