Keeping a backup of your data is a hugely important rule to almost all sorts of computing. While cloud computing through something like Chrome OS helps take care of that for casual applications, until everything is cloud-based users will need to take care of things for themselves.
According to winrumors, a new feature that might make it into Windows 8 is something that will potentially be called History Vault. The new feature will supposedly make use of the Shadow Copies that Windows makes when files are modified.
History Vault could end up working much like Apple's Time Machine feature for Mac OS X, which keeps a record of all files added, deleted and modified. Users of Time Machine can browse back to see a file's history and restore it to the present system state. Time Machine also keeps a complete copy of the system for full backup and migration purposes.
It's a handy feature for Mac users, and something like it would be a great addition to Windows.