For businesses that rely heavily on Microsoft back office products, DPM 2007 has a lot going for it. The product provides near continuous backup for products such as Exchange, SQLServer, SharePoint server and more.
Continuous Data Protection, or CDP, is an abused term. Real CDP requires fat pipes usually between similar storage arrays and usually - though not always - comes from the storage vendor. This is expensive stuff, and is often beyond the needs of many businesses.
In true Microsoft fashion, DPM 2007 is a reasonable alternative to what can be a very costly technology. DPM replicates state dependent systems like Exchange and SQL Server as often as every 15 minutes. the system manages moving those snapshots (up to 512 per system)to external disk systems and to tape archive. Bare metal recovery is part of DPM's capability.
The software is definitely affordable at $722 for the DPM servers and $199 for the standard file agent.
Microsoft uses the usual mechanisms to achieve protection. The system stores only changes, which amount to a series of incremental backups usually to disk. Archiving can then be done on the backup rather than burdening the production system.
The system is typical of Microsoft insomuch as it is very simple, but may lack some of the detailed configuration options of competitors. That said, for Microsoft shops, it's absolutely worth a look.