Say you send MS Mail and Internet Mail from work, but you want to use
   the same copy of Exchange (and the same machine) for you home Internet
   Mail too. You can't load multiple copies of Internet Mail in one
   profile, but you can create a second (or third, or fourth) profile,
   add Internet Mail to it, and use different settings. All Exchange user
   settings go in the active Exchange profile.
   
   To make a new profile, bring up Inbox properties and hit "Show
   Profiles". Then select "Add". The Inbox Setup Wizard will run a second
   time, prompting you for a new profile name, and prompting you through
   all the setups of all installed mail clients. You can enable or
   disable whatever mail clients you wish. Then, when you get to the
   Personal Address Book and Personal Folders setup screens, be sure to
   specify a unique filename for the address book and mailbox, different
   from any previous profile. The wizard will create new files for you if
   they don't already exist. You CAN use the same address book (.PAB) and
   mailbox file (.PST) in multiple profiles, but why cause confusion?
   Then, in Tools/Options within Exchange, enable "Prompt for a profile
   to be used". This way when Exchange runs, you can choose the profile
   to run.
   
   You need to exit and re-start Exchange to swap between profiles. Be
   sure to allow it to completely exit (at least wait until the fax icon
   disappears) so it logs off from the services in the first profile.
   
   Profiles are cool for Exchange-enabled apps, because the apps will
   store their user settings per-profile. Internet Idioms, for example,
   can keep a unique signature for each profile. Schedule Plus for 95
   also keeps unique schedule books and contact lists per profile. You
   don't even need to have a mail client; a profile only needs the
   Personal Folders and Address Book services.
   
   Exchange stores profiles in the user portion of the Registry, so
   User Profiles apply here as well. Each user can have their own
   set of Exchange profiles, of if you don't want to be bothered with the
   "Prompt for profile to be used" requester, use a single profile for
   each user. This is especially useful of you have roving users that use
   Schedule Plus for 95; if you keep the schedule and message files in
   your home directory, all of the books will follow you around the
   network. Now that's cool.