I can't believe I haven't heard of this blog before but I'm delighted that it has finally come to my attention. Floatingsheep.org is dedicated to mapping and analysing user generated Google Map placemarks. The results of this analysis provides a fascinating insight into the socio-political make-up of places.
The blog has a series of interesting posts examining what Google Maps users are adding and where. For example this post compares the number of book stores and churches added to Google Maps across the USA.
The analysis finds that, for the most part, the relative prevalence of book stores occurs in and around the big cities and the eastern seaboard. Whereas suburban areas surrounding large population centres show a near-universal favouritism for churches.
Another great example is this look at User Created Geographies of Religion, which looks at religious references in user-created content on Google Maps around the world.
There are a number of other interesting analysis of user-created content on Google Maps. I strongly recommend you visit floatingsheep.org if you have a few hours to kill.