Data mobility is the ability to access your from anywhere in the world as long as you have a computer and internet access.
For business storing their data in a server in their office, VPN (Virtual Private Network) is one way to access the data remotely.
Third party services are available for this kind of data mobility access. iDisk is one of them.
Carbonite itself is a backup service but also can be configured to act as data mobility access.
Windows 7 got new technology using RPC over HTTPS to access data remotely.