Microsoft removed the very useful Identities feature from OE when it changed
it to Windows Mail.
I've written a program that mimics this feature Windows Mail. This allows
the user to impersonate different users and maintain segregated settings and
message stores for each Identity within a given Windows user logon space.
This Identities capability can allow for a single user to have multiple
settings, or multiple users can maintain separate settings and message
stores within a single user space. (Note, however, that in such a
circumstance, the other users can access each others' messages via Windows
Explorer, so there is no security / privacy. That can only be achieved by
different user logons.)
For a screen shot and a description of its features, see
Stephen L. Cochran, Ph.D.