Why Do Dowsing Rods Seem To Work?

Thanks to "Privacy Act" for the first comment to the blog.

To paraphrase his question - If the product doesn't work, why haven't the customers who have bought the Sniffex or other similar products complained? And if the Navy testing showed the product did not work at all, how can dealers keep selling them?

Here are some possible explanations of why people might believe the rod works, even if scientific testing has never shown that to be true:

http://skepdic.com/ideomotor.html
http://skepdic.com/dowsing.html
http://www.randi.org/library/dowsing/
http://www.skepdic.com/essays/dowsingfordollars.html