Many companies have limits on the amount of space an individual’s e-mail account can take on the server. In fact, even if you are a home user, your Internet Service Provider (ISP) probably has similar mail storage limits.
With a Personal Folders File, you can store your e-mail message offline (or, off the server). This way, you retain access to the e-mail without using the storage space on the server. See? Everybody wins.
But, there is one caveat – since Personal Folder Files are stored off the server, it’s up to you to make sure that file is backed up on a regular basis. And, because these folders are not stored on the e-mail server, if you use the Internet to view your e-mail from off-site, you won’t have access to any messages stored in the Personal Folder File.