I never thought about identity theft very much until it happened to me. It is an easy crime to commit. All you need is a little information about a person or business to create checks or apply for credit and do a world of damage to the victim's financial and credit history.
Mail is a likely place to find that information. Criminals either put through a change of address for you or steal mail right out of your mailbox.
To deter mail being taken from your mailbox you can buy a new mailbox that has a lock with a key,
install a mail slot in your door or rent a Post Office Box.
An article you may find informative: Your Risky Mailbox: Identity Theft 101 http://idtheft.about.com/od/identitytheft101/a/Mail_Theft.htm