We have just concluded a study in which we asked how end users use e-mail at work. Here are some highlights.Each business day, users send an average of 29 e-mail messages and they receive an average of 59. This means that in a typical work year, a typical user will send and receive a total of nearly 23,000 messages. If we very conservatively assume that the typical message is 50K bytes, factoring in the significant percentage of e-mail that contains attachments, then the typical business user sends and receives about 1.1G bytes of e-mail traffic annually. At a minimum, this figure needs to be doubled, because e-mail that is sent is also saved by the sender, sent to multiple recipients, and so forth.The average user spends 77 minutes each week managing his or her mailbox, cleaning out old messages, filing old messages and attachments, and so forth. This means that during a work year, the typical user will spend about 1.7 weeks just managing their mailbox, or about 3% of their time at work. Assuming that the typical e-mail user has a fully burdened annual salary of $60,000, then the productivity cost alone of managing a mailbox is nearly $2,000 each year.Ninety-four percent of users refer to old e-mail when answering current e-mail, and 78% of users at least sometimes have trouble finding old e-mail that they know they have. This indicates a critical need for some sort of archiving capability to index old e-mail and make it more easily accessible to users, particularly since our research found it takes a substantial amount of time to find e-mail that is older than a couple of weeks. An archiving system can significantly reduce the amount of time spent by e-mail users searching for older information in their message store.