There are several reasons for this:

  • A user using POP3 client software like Outlook can set it to read and download email but still store a copy of the mail on the server to be accessed in the future.
  • Users use our webmail feature only, but they do not delete any emails or download it.
  • Some web mail providers, like Hotmail, allow users to grab mail from our servers and still keep a copy on the server. Therefore the mail server still has a copy of mail that has been read/downloaded.