I just watched a CNN special on "How to Rob a Bank." It mostly dealt with how individuals stole from banks using various forms of identity theft. Now, I'm not paranoid about such things, but it seems that one of the more common ways to be victimized is to have credit cards opened up in one's name by others. It also appears that the most common way that this happens is through those credit card applications received in the mail (how many do you get a week? Maybe one a day?). Clearly, such credit card offers should be shredded or torn up immediately, but there are still a number of ways that they might fall into the wrong hands.
The best way to avoid this problem altogether is to prevent companies from sending you credit card applications in the first place. The way that the companies get your information is through the three credit reporting bureaus, and fortunately, those bureaus must listen if you tell them not to give out your name. There are two different ways to do this: online or by phone. You can call 1–888-567-8688 or visit https://www.optoutprescreen.com. You have two options for opting out of credit offers -- if you do it online or over the phone only, you're off the list for 5 years, and when the mail starts to come again, you'll have to opt out once more. Or, if you fill out a form and mail it in, you can opt out for life. Note that opting out does require giving them your social security number, so before you do, make absolutely sure you're at the right website. If you have doubts, call the number.
It's a wonderful thing! I did it about 6 months ago, and I've not received a single credit card offer in the mail.