Previously, for the most, when a SSIN alert was sent to a property, it was downloaded and stored on a local server or local computer. As more and more people and/or SSIN alerts were added to systems, data management became a real issue.
Now, with VC7, you don't pull the SSIN alerts in locally anymore. You now have the equivalent of what is a view of the data on the server. There is less space utilized on local machines, allowing you more space for your PDE/X-LSTs instead.