Here are some sobering statistics. Seven of every ten people use the same password for more than one web site they sign on to. 64% have written down their password at least once. A recent study found that 80% of Londoners have never changed their bank PIN. Women are twice as likely to choose the same PIN for multiple cards. Some 24% of us must remember five to seven passwords, while 12% need to recall more than 15. Another study found that 88% of respondents had forgotten a password within the past two years and had to request to have it reset.

What I see here is a vulnerability to identity theft, a threat ranging from annoying (trashing your Facebook page) to serious (accessing your bank accounts). So how can you tighten up your password creation without losing your mind? CSOOnline.com suggests this scheme:

1. Choose a memorable phrase at least five letters long. For example, let's use the phrase "Walletpop is a Very cool site." Take the first letter of each word, WiaVcs. This becomes the root of your password.

2. Replace at least one letter with a symbol. I'll substitute a dollar sign for the s, leaving us with WiaVc$ as our root.

3. Now suppose we want to create an account on AOL Instant Messenger. We could add the last letter of the site to our root- WiaVc$r.

4. We then count the number of letters in the last word of the site; in this case, the word "messenger" has nine letters. We add that number to our password, and end up with WiaVc$r9.

I'd then suggest running the result through Microsoft's password checker to make sure the result is strong. This one is.

Take care with your passwords. And don't write them down and slip them under your computer. You're just inviting trouble.

And the next time you visit your bank? Change your PIN. Just in case.

Read more WalletPop stories about identity theft