"The very four digits that Amazon considers unimportant enough to display in the clear on the Web are precisely the same ones that Apple considers secure enough to perform identity verification..." Honan wrote.Four digits, when combined with my home address and bank account number were all it took for me to gain on line access to a dormant checking account at my bank and enable fund transfers. If I were fond of the various auto-pay options, there would be a dozen or so companies that would have my checking account number, any pretty much anyone in the world can find out my home address (I own a house, so it's in various public records).
Segmenting ones on line life into non-overlapping buckets seems like the best way to break the daisy chain that led to the hack and data loss. I've followed that principle. I try to maintain separate, non-overlapping e-mail addresses and passwords for any on line account that either is connected to something that could cost me money if it were compromised, or is used for account verification for any of those accounts.
I have lots of e-mail accounts and addresses. It's a pain in the azz, and it's only a partial solution.
Read: ARS, Wired
More thoughts here.