Outlook Express Identities
If there is more than one person accessing email on the same computer, using Outlook Express's Identity feature helps protect the privacy of each individual's email messages.
From the Outlook Express Help file:
What are identities?
Creating identities is a way for several people to use Outlook Express and the Address Book on the same computer, and maintain privacy for each account. For example, you and a family member may share a computer. If you each create an identity, you would each see your own mail and your own contacts when you log on under your identity. Once your identity is created, you can organize your contacts the way you want them by creating subfolders.
Identities are also useful if you have more than one email account.
It is easy to set the identities up, here is how:
First open Outlook Express. If you have already setup more than one email account, go into the Tools option and select Accounts. Delete all of the email accounts except one. This will be the first Identity account. Add this account, select a user name & password.
Now click on the file menu & select Identities/Add new identity.
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Next set up the new identity.
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Setup a password.
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Now switch Identity, (from the File, Switch Identities) click on the Tools menu
& select Accounts/Mail. Add the email account information for the new
Identity.
Now from the File menu, select Exit and Log Off Identity. The Next time Outlook
Express is opened, you should see this:

Highlight your identity, type in your password and click ok. You will then be in
your Outlook Express Inbox. Your email is now private from other users on this
computer.