Mozilla (or Thunderbird, or Netscape, which are very similar) can be set to remember your email login information (username and password) as well as usernames and passwords for various Web sites you visit.
While it is convenient to remember certain Web site passwords, you may want to think twice about allowing Mozilla to remember your initial login password, as this leaves your account open to whomever has access to your PC.
You are asked when you first setup email if you want Mozilla to remember your password -- it is Hightly Recommended that you don't allow this!
If you've already said yes, and wish to set it back, go to Edit, Preferences, Mail & Newsgroups, and select Privacy and Security, Passwords, and uncheck the Remember passwords box.
If you wish to also remove all of the stored username/password information from Mozilla, you must click on the Manage Stored Passwords button.
... and click on Remove All
If you don't want your initial email password remembered, but *do* want to have Mozilla remember Web site password information, you can then re-check the Remember Passwords box and it will only affect the Web Site passwords.
When you visit a Web site that requires authentication, Mozilla will ask you if you want Mozilla to remember the authentication information.
