Kevin Remde (Full of I.T.) brings to our attention a great quick-reference chart of Windows Server 2003 features, comparing SP1 to R2 for each edition. I like this approach, and I agree with Kevin that "All of our products need a page like this, and it should be one of the first links you see on the product's home page."
Data Protection Manager isn't as complex as Server, naturally, but this would still be a great method for communicating our changes in the next version. I'm going to set myself an Outlook reminder for later in the development cycle to revisit this chart and the idea behind it.