Advantages

• Among the many advantages to the mbox format is its simplicity. Because each mailbox is a simple text file, the mailbox is human-readable. This simplicity also makes it relatively easy to repair a corrupt mbox file by opening it in a text editor, finding the corrupt section and deleting it. This simplicity, as well as its UNIX origins, have helped make mbox a ubiquitous format. Many email programs that do not use mbox as their native format still feature the ability to import and export mbox files.
  
  

Disadvantages

• Although the mbox format's many advantages are derived from its inherent simplicity, its disadvantages are often a byproduct of that same simplicity. For example, since each email in an mbox is differentiated by a simple "From" line, care must be exercised to ensure that the line is unique enough to not be encountered in the body of an email. If a sentence in the body of an email began with the same sequence of letters as the "From" line, the email client would incorrectly believe it to be the start of a new email. Since all of the emails are stored in a single text file, a mailbox must also be locked when in use to prevent multiple, simultaneous processes from conflicting with one another and corrupting the mailbox.
  
  

Maildir

• Maildir is a common alternative to mbox. Rather than using a single text file for each mailbox, maildir mailboxes are directories on the user's hard drive. In each directory, or mailbox, each email resides as an individual text file. Like mbox, this makes it very easy to open, read and understand a maildir mailbox. Unlike mbox, because each email is an individual file, it is not necessary to lock the entire mailbox when various processes are accessing it.
  
  

Database

• A database is another common alternative to mbox. Rather than store emails in text files, all emails are stored in a database. Some email programs use one monolithic database containing the emails for all of a user's mailboxes. Other programs use an individual database for each mailbox. Because each email is a record in the database, unlike mbox, there are no issues with differentiating individual emails. Whereas mbox and maildir both require a mechanism to index emails for searching, information search and retrieval is an inherent strength of databases.