You'd be amazed (well I was) at the information about Americans that's already public.
Pick a random name and google it or try it in voterrecords.com or mylife.com or beenverified.com, or one of the other sites those link to.
Eg I tried Anthony Mackie (like the hunky actor
). And 'tinternet is more than happy to tell me all this about some random person called Anthony Mackie:
voterrecords.com/voter/4691562/anthony-mackie
Anthony M. Mackie (age 62) is listed at 291 High Plains Drive Orange, CT and is affiliated with the Democratic Party. He is a male registered to vote in Connecticut.
Overview of Mr. Anthony M. Mackie
Lives in: Orange, Connecticut
Phone: (203) 891-0600
Age: 62
Gender: Male
Anthony Mackie's Voter Registration
Party Affiliation: Democratic Party
Registered to Vote In: Connecticut
Registration Date: 10/06/2008
Voter Status: Active Precinct: 00
Congressional District: 003
Senate District: 014
It also gives likely family members, neighbours, and offers a "Full Background Report" (think I'd have to pay for that, and I think it includes convictions and maybe financial info).
Some of these sites also list date of birth in the free info, where they've been able to find it.