MIM - Multi-Purpose Internet Mail Message File is a beneficial file you can use when it comes to your email. Many different email applications make use of this format for different reasons. Everything that is within this file is mainly used for support of the 8-bit content. File attachments happen to be one of them. This can be replaced by the usual 7 bit messages that are used through email instead. You can view this type of view as apart of an email or individually. Email programs usually decode this format, but the bottom line is that they are worth having on your system.