Here is an interesting article which tabulates terminology changes from MS Exchange Server 5.5  to Exchange Server 2007; there are quite many changes been made between these versions, added/removed quite many features.

Although this table doesn't include all the features, but it can be used as a starting point to help yourself...

Exchange Terminology changes in Exchange 2007

Microsoft, Exchange Server, Exchange Server 5.5, Exchange Server 2007, Roadmap, Guide

Source:→ MSDN Blog