Millions of people a year are flocking to online sites, such as Facebook and Twitter, where they can share their lives, with friends and strangers, without giving much thought to the huge computer databases they are building.
Those databases are filled with life's details. Personal details and trivial details. Intimate details and silly details. Lofty details and mundane details.
And somebody is watching. Or wants to be.
Social scientists hope to tap into that vast store of digital data to find out what makes us tick.
"What people ate for lunch at the turn of the 21st century might be among the information that helps paint with more colors and a finer brush," says Library of Congress spokeswoman Gayle Osterberg.
And people are supplying that data more and more.
