Catalog Zip Code Notice For Free

The caveat is, we assume you mean your 5-digit ZIP code. That is safe. If you give out your ZIP+4 (which I doubt you meant), those 9 digits can narrow down a single point of delivery, or very narrow point like one side of a city block, a floor in an apartment building, or a company.

And some credit cards, like American Express, prompt retailers to ask for a ZIP code as a form of fraud protection. If you're paying with cash, giving a cashier your ZIP code isn't going to result in any unwanted advertising?they'd still need your name for that.

A ZIP Code is a 5-digit number that specifies an individual destination post office or mail delivery area. ZIP Codes determine the destination of letters for final sorting and delivery. Each ZIP Code designates a collection of delivery routes used by mail carriers and areas serviced by the USPS.

Alone, your ZIP code might not be of much value all by itself, but criminals will take that information and post it on underground sites where they buy, sell and trade bunches of personal information. From those sites, criminals can purchase enough of your personal information to use it for fraud.

So what do the extra numbers mean? These last 4 digits represent specific delivery routes within delivery areas. This extra detail means an even more precise matching to a more granular level. It could represent a handful of houses on one side of a street, or even a single building that receives a high volume of mail.

Stores want your ZIP code because, combined with your name from your credit card, they can use it to find out other information about you from commercial databases, like your full mailing address. They may even sell the information to data brokers, who sell it to other marketers.

Disclosing ZIP codes allows "people [to] track their purchases. It creates a profile and that information can be shared with other companies and that's dangerous to have that information in one area," says lawyer Gene J.