When a product is released, there are a lot of lessons learned as to understanding theproduct, upgrading the environment, keeping the current on the latest hotfixes and service packs, and decomissioning server. I have put together a collection of KB articles around Exchange 2007 which are helpful to understand when planning, or maintaining your Exchange Organization. 

 With the addittion of Standby Continuous Replication (SCR) in Exchange 2007 SP1, there are some new concepts to understand. For example, a Storage Group that is a source for SCR can only have one mailbox database. To get the technical details see the TechNet TechCenter Article on SCR.