Yes, it's time for the National Archives to release another decennial Census-worth of data on our forebears. This time it's the 1940 Census that will become completely available online, as of 9 A.M. EDT today.
Every 10 years the Census Bureau counts us all, as well as collecting information on where we live, how we work, etc. The aggregated numbers resulting from each Census are available from a few months to a few years after we've filled out our forms.
But the actual forms, with names and addresses, legally cannot be released until 72 years after the Census was taken. This delay protects the privacy of most of the adults counted, and the eventual release is quite a boon to their descendants doing family histories.
At the 1940 Census website you can find a step-by-step guide to finding information in the voluminous files. Plus see an informative video that describes the herculean task the Archives undertook to digitize the previously microfilmed records.
National Public Radio has publicized a bunch of fascinating tidbits from the Census and the year 1940 in general. And they also display this promotional video, made by the Census Bureau to encourage cooperation with the Census takers:
Hint for a real entertaining hoot: take a look towards the end of the video at the "marvelous" punch card machines the Bureau is using to compile all the data!