Privately owned public space map

Ever since Minnesota's Kristine Miller wrote her book, Designs on the public: the private lives of New York's public spaces, I started paying closer attention to the hidden public spaces in various cities.  Like NIMBY and LULUs, they need a good name to catch on so some people are calling them Privately Owned Public Open Spaces or POPOS.  So it caught my eye when Strange Maps blogged a map of POPOS in San Francisco.  As they point out, some of these a well-kept secrets.  Well, they were.