Marked for deletion: an analysis of email data

What characteristics of an email message make it more likely to be discarded? Statistical analyses of a set of deleted and non-deleted messages revealed several factors that were important in predicting the fate of a message. After controlling for the owner of the particular message, four factors turned out to be most important: history of communication with the sender (messages sent to and messages received from), intra-organizational vs. external sender, and size of the recipient group.