Why do this?
You can store E-mail messages locally on your computer. This allows you to keep e-mail messages that you don't want to keep on the e-mail server. Therefore, locally stored e-mail doesn't count against the quota of space allocated to you on the e-mail server.
Access locally stored e-mail
You can access locally stored e-mail only from the computer where it is stored. However, you can't get to these messages from another computer.