I think this might be disturbing...
About a week ago, I got an e-mail from my bank about a credit card charge that was unfamiliar (I have it set so that I get a notice for any charge over $1) I called the credit card company and told them I did not make the charge. They went over the various ways a charge might appear and concluded that it might be fraudulent. They cancelled that card and sent me a new one. It arrived today. I have a list of trusted online companies that have my information (newspaper, local government toll bridge, etc.) and I started going through the list, making the change to the new card.
When I got to Amazon, I discovered that My Account already had the card.
Your Account > Your Payments > Settings showed the last four digits of the NEW card. WTF? The new card just arrived today. How did Amazon get the information before I did?