void man();

"There are only 7 billion people on the planet, and only about a billion on the Internet. Every fact about a person (are they male or female? Where they live? Do they listen to Brian Eno?) slices that number down by a significant fraction. If you have enough facts about a person, (33 bits of independent facts, it turns out, because log 2 7,000,000,000 = 32.7) you can determine who they are."

—Websites that collect and republish seemingly innocuous facts about their users are often vulnerable to data mining.