What is new about this, is that it is none of the three things that your quote listed as possibilities. The new thing is a remote storage that has a smartly synchronized local "cache".
Nothing could prevent a remote filesystem to have a local cache, actually this is what every remote filesystem would implement quite soon.
The real novelty of Infinit is that you can mix and match multiple storages and build a unified filesystem with encryption on top of this. Roughly something like truecrypt over aufs over (sftp+local fs+s3fs+whateveryouwantfs)
The real novelty of Infinit is that you can mix and match multiple storages and build a unified filesystem with encryption on top of this. Roughly something like truecrypt over aufs over (sftp+local fs+s3fs+whateveryouwantfs)