[mjevans]

I think at a high level users might be OK with paying for their actual stored file size.

A way of improving the storage size might be to allow the user to white-list (with some defaults) folders more likely to have 'third party' files (E.G. C:\\Windows, C:\\Program*, /usr/) either excluded if they're on a list of common files or de-duplicated with a public list of common files (and check-sums). It would be useful to add-on programs and scripts if that list were public, and if a way of cloning those files in to a discounted pool were possible by 'uploading' them again (to ensure the customer actually /has/ that file and thus presumably the right to restore it).