With the right computer models and data sets, data miners and the numerati can determine a US citizen’s real name with just three pieces of seemingly unrelated information.

According to a Carnegie Mellon study, as many as 87 percent of US citizens can be identified by name, even if the only three things they disclose about themselves are 1) their gender, 2) their zip code and 3) their date of birth. [ source: book "The Numerati", page 13, by Stephen Baker ]

Yes, even if you withhold your real name, pieces of seemingly harmless personal information can be crunched and analyzed to identify you.

Think of how many times you provide even more personal information than that to people and organizations.