This KMZ file (7.4 mb) aggregates basic population and poverty demographics for the Zillow neighborhood boundaries.

I used census block group data from the SF1 and SF3 file of the 2000 census. The map is color-coded by the percent of the population living at or below the poverty level.

Neighborhood boundaries are sorted by city and state in the sidebar. For faster display, the initial map shows Washington, DC only. Click boxes on the sidebar to display additional states.

Use Ctrl-click on the map to display the population and poverty stats by neighborhood.

Block groups are often split by neighborhood boundaries. For the population data by race and ethnicity, it is possible to develop more accurate estimates using block-level data from the SF1 file. However, for the poverty data, block groups represent the smallest unit reported by the Census Bureau.

In a few instances (less than 1 percent), neighborhood estimates could not be derived due to topology errors when converting from the original source Zillow shapefiles. (This includes all of Wake County-Raleigh, NC). You can identify these discrepancies by overlaying the non-color-coded KMZ file posted in the entry above.

For more detail, remember that you can always overlay SF1 and SF3 datasets from gCensus .

See also this blog post with a Google Map example.

As noted above, the neighborhood boundaries are made available in shapefile format by Zillow.com under a Creative Commens License.