I see that in the database dump, there are more than 10 000 places in United States with feature code PPL (populated place) and a name that contains the word "subdivision".
For example, there are 2 "Little Italy (subdivision)" (one in California, the other in New York). Other places in this case seem to be Mobile Home Parks.
Maybe I am not understanding the purpose of the different feature codes, but... shouldn't these 'subdivisions' be considered sections of populated places (PPLX)? In the case of Little Italy seems clear to me, in the other cases I don't know, because after doing some research I've discovered that there is something called CDPs ( http://en.wikipedia.org/wiki/Census-designated_place ) in US, and then I thought that maybe some of the subdivisions are CDPs.
The data for the US is mainly the GNIS (Geographic Names Information System) data set from the USGS (U.S. Geological Survey).
The code "ppl" was mapped to the featureclass "P" and the feature code "PPL" :
I have now updated our database and changed the feature code PPL to PPLX for all PPL in the US with 'subdivision' in the name.
I don't know how close the USGS works together with the US census, so I cannot tell whether this is related or not.