In addition to email management, Outlook's contact and diary management functionality means that, for many organisations, it is used as a primary reservoir of critical business information. 

One of the most useful features of Microsoft Exchange is that a master copy of all Outlook data is stored on the email server within the Exchange database. 

Should you lose your laptop or if the hard drive of a PC becomes corrupted, the Outlook data is not lost with it. You can immediately access your Outlook data through Outlook Web Access and, as soon as your equipment has been repaired or replaced, you can synchronise Outlook with the Exchange server and your data is restored to the new computer fully intact.