I wrote this in March 2012, around the time that 4square switched from Google Maps to #openstreetmap . +Wikipedia recently made a similar decision. There are pro's and con's to this, as well as the question of whether crowd sourced mapping makes sense at all, open source or not. (Google Maps is crowd sourced but not free, Open Street Map is crowd sourced AND free). I believe there are specific situations where it can work well. But you'll need to read my full post to find out more
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