Do you delete unread e-mail?
We don’t delete unread mail.
However, if you have more than 25,000 unread messages in a mailbox, we may archive them into a “tar.gz” file to prevent mail server performance problems.
If this happens, we’ll replace the unread messages with a “placeholder” e-mail message explaining what happened. If you want to view the archived messages later, just let us know and we can expand them back into your mailbox.
When we say “more than 25,000 unread messages”, we don’t mean that you actually have to read a message with your eyes. Simply logging in using Webmail, or making a successful POP or IMAP mail connection from your computer’s mail program to our servers, marks all waiting mail as “read” and prevents it from being archived, whether or not you actually read it.
This policy controls the size of abandoned mailboxes while making sure we don’t permanently delete a message you might want. Most ISPs have a much more restrictive policy — for example, Comcast deletes unread mail more than 45 days old, and AOL deletes unread messages more than 28 days old.