A receptionist collecting job applications doesn't need to see employment-seekers' Social Security numbers. Professors don't need to post grades by students' Social Security numbers. Customer service representatives don't need to know Social Security numbers to respond to consumers' complaints.

"There's a general uneasiness in the public right now," said Linda Foley, founder of the Identity Theft Resource Center, a nonprofit that tracks identity theft and data breaches. "There has been a loss of public trust in e-commerce, online banking."

The ITRC has counted 167 data breaches in the first three months of 2008. These invasions of private information — Social Security numbers, bank accounts, credit card numbers — could affect more than 8 million Americans.

But identity theft is not inevitable just because data has been leaked. Even though a breach notification letter is alarming, "the majority of these people will never become victims of identity theft. Don't panic," said Foley.

If a breach happens to you, act quickly. Put a fraud alert on your credit report, cancel affected credit and debit cards, close or change leaked account numbers, check your credit report at Annualcreditreport.com once every four months and put new passwords on sensitive information.

And, pre-emptively, give out your Social Security number as infrequently as possible.