Screen your e-mail without download Mail Preview lets you see your mail before you download it. Because of all the viruses and spam going around, you often don't want to open all of your mail. Since Mail Preview doesn't actually open the messages, you can't get a virus by reading your mail. You can also delete all the incoming spam before it gets into your regular mail program (MS Outlook, MS Exchange). If you choose not to delete an item, it remains on the mail server so you can read it later. This can be very useful if several people are using the same mail account from different computers.