"Locking down" Exchange .. IMAP?

["Mark G. Spencer" <mspencer () evidentdata com>]

I'm curious how small companies try to "lock down" and secure their email
using Microsoft Exchange, both to better control email and also better
protect their information  .. I was thinking the use of IMAP, forcing server
side email and SSL authentication may be a good start.

Any thoughts?

Thanks!

Mark