Centrally recording video from remote sites is as frequently claimed as it is wrong. It is an exciting concept that fails due to basic technical details. Vendors claiming their system eliminates local recording are almost invariably wrong. The problem is simple - the cost of long-distance (WAN) bandwidth is very high and it destroys any savings you might achieve from eliminating the local device.
[UPDATE 2012: While VSaaS vendors have promoted such an archictecture, the reality 4 years later is that centralized NVR recording is still not viable for anything more than a trival number of cameras per site and even then the economics remain poor.]
You are a retailer, organization or corporation with multiple stores, locations or branch offices. Today, at each of those locations, you have a DVR with storage at each of these remote sites. It's expensive to buy all of these units. It is hard to maintain them because when they break, someone needs to be dispatched far away.
It would be far better if we just had IP cameras and used an IP network to stream the video directly from the cameras to a centralized storage cluster. This would significantly reduce equipment cost, increase storage utilization and make fixing hardware failures easy because the equipment is all in one simple to access location.
The concept is bulletproof. Unfortunately you cannot deploy concepts.