Good olde Doug has done it again. Check the docs out they are great
The ability to continue to provide a full service to your user community in the unlikely event of the loss of a datacentre is an increasingly common requirement. The use of Continuous Replication (CCR and SCR) with Exchange 2007 Service Pack 1 is an obvious choice in providing data availability and site resilience. One advantage to this approach is that the reliance on expensive storage replication solutions is eliminated. In addition, a disaster recovery scenario is managed from within one team rather than several teams. In most cases the messaging team can manage the restoration of service without the intervention from the storage team, or from a remote 3rd party hardware vendor for example. The use of Exchange Server data replication as opposed to storage replication solutions also gives us more options to use PowerShell scripts to assist administrators in simplifying and controlling service and data recovery and application-based replication is generally superior in assessing the health of the data being replicated than hardware or storage-based replication.