SVS is the Altiris solution for software virtualization.
This client service activates aplications for a user, based on his group membership.
Therefore an application or set of applications is "traveling with the user". This is an ideal tool if your users are often switch from desk. 
The program remains in the background and queries on a defined time the group membership to activate programs.
However activating apps also can be done via the login script this tool has some benefits compared to a script:

It remains active
It's creating a log file of all activities.
It can automatically import an SVS package when not available on the system.

Update: this software applies to SVS 2.1
These days Symantec adopted the technology and named it Symantec Workspace Virtualization Admin.
Symantec changed  the used WMI classes and therefore it's not working on the Symantec product.
I stopped further development.