Hi All,I wonder if anyone here can help me clear something up. As far as I can tell, the Exchange 2000/2003 database's are relational. Which I presumed to mean that if 10 people with mailboxes in the same Exchange database get copied in on the same email, the database would actually only have one copy stored even though they appear in 10 different inboxes.A colleague of mine is disputing this, he says it's a flat database type structure, which is fine, but I'd like to know the facts either way.Is this true? Is their any kind of storage cleverness going on here?Thanks in advance for any info Cheers,omnisound

ESE Databases in Exchange 2000/2003 (and 2007 for that matter) supports Single Instance Storage (SIS), which you can read more about here: http://support.microsoft.com/kb/175481