When you log into Facebook, Amazon, LinkedIn, or any of the number of web services you use every day, you don't want to type in your username and password every time. All the major web browsers offer the option to save your passwords for you and auto-fill them — which is very convenient, but not that secure. What if someone else uses your computer and can log into your personal email account because your password is saved? Or worse, if your laptop is stolen and those sensitive login details are auto-filled in for the thieves' convenience?

There is a way to have both the convenience of auto-filled passwords AND security. The free Firefox web browser offers a "Master Password" feature that locks up all your saved passwords into an encrypted file.

Think of your web site usernames and passwords like the keys to your car, home, office, and safety deposit boxes with their locations included on the keychain. If you keep all those keys in a shoebox and leave it somewhere (or it gets stolen), anyone who can get to the shoebox has access to all your important spaces. Firefox's master password is like keeping all those keys and addresses in a safe, with a single key. Even if the safe gets stolen, it'll be virtually impossible for the thief to open (compared to that shoebox).

Here's how the Firefox master password works in practice: Once you've set it, any time you launch Firefox to start browsing, when you go to a page that requires you log in — like Facebook — Firefox will prompt you for your master password (not your Facebook password, your one master password, the key to the safe). Enter that and Firefox will unlock all your stored web site passwords and automatically fill them in for you during your browsing session. You only enter the master password once during a browsing session to auto-fill saved passwords as you browse. Once you close your browser and reopen it, you'll have to enter it again.

It's a little bit of an inconvenience to enter your master password every browsing session, but much less of one than entering your password for every web site you use.

When you use a master password, if you shut down your browser or computer and someone else who doesn't know your master password tries to use it, they won't have access to your saved passwords, and they won't get filled in on various web sites.

Here's how to protect your stored passwords using a master password in Firefox. From Firefox's Tools menu, choose Options. Click on Security, then on the "Saved Passwords" button. From there you can set or change your master password.

If you forget your master password for Firefox, you can reset it. You'll just erase all the stored web site passwords when you do.

Of course, you've got more passwords to track than just for web sites — there are also computer passwords, Wi-Fi network passwords, and even ATM PIN numbers and lock combinations. Next week we'll take a look at how to securely save those kinds of passwords outside the web browser.

Do you use your web browser's saved passwords feature? Tell us how in the comments.

Well, September has come and that means a lot of different things to a lot of different types of retailers. Yahoo has posted a nice list of different events to keep in mind on the Yahoo Search Marketing Blog.

According to Yahoo, September is the month for:

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