In this day and age of rampant identity theft thanks to the Internet, it’s important to protect your own privacy when it comes to distributing your resume. My book discusses some techniques for minimizing your exposure to identity theft.
An additional tip I can give — not included in the book — is this: on every page of your resume, include a header that says "confidential" (in caps and maybe also italics, too). Even though this does not have any legally binding power, it can remind the reader of your resume that you expect him or her to keep your resume in confidentiality.
One thing that I’ve seen people do but I don’t practice myself is including a tiny tracking number at the bottom of the last page of your resume. For instance, if you send your resume to J.P. Morgan, you might put down "ver. jpm0702" in a very tiny font at the bottom right of the last page. That way, if someday your resume shows up at some unexpected location, you’ll be able to know which recipient was at fault. Then you could contact your lawyer about doing something about this clear act of negligence.
Book update: I approved the final galley on Sunday and the book should be available in three to four weeks.