The tie in is pretty obvious, Seagate is looking to go from low margin businesses (drives) to higher margin businesses (services), so this is a natural play. It can brand Evault to something silly like Seagate Core 2 Duo, and get a customer recognition boost from it.
The fact that Evault needs a lot of drives doesn't hurt much either. This looks to be a good thing for Seagate, and possibly a good thing for users until they realize how long it will take to restore a failed 500GB drive over a DSL connection. ยต