Where statistics meet individuals: US Census Bureau publishes the 1940 Census records.
http://www.census.gov/1940census/index.html
http://www.archives.gov/research/census/1940/start-research.html
And lots of interesting infographics
http://www.census.gov/1940census/then_and_now/key_comparisons_years.html
Blog about Stats 
Bloomberg, Apr 12, 2012 ‘Americans have downloaded 134 million document images from the 1940 census since individual records were released April 2. That’s 2 million more images than the number of Americans who were alive when the census was taken 72 years ago.’ More: http://www.bloomberg.com/news/2012-04-12/most-wired-generation-meets-greatest-generation-in-census-frenzy.html.
Thanks Alain for this hint.