A decentralized storage net that offered append only extents, under various integrity / authenticated / redundancy / expiry models, could be interesting. At cost for guaranteed expirys, free for other lesser methods. However your indefinite arbitrary incommunicado detention could always exceed such provisioning... most networks just aren't there yet. There's enough unused space on all the planet's storage devices to develop some incredible decentralized applications that can utilize it. We're starting to see the first few entrants to that space. Most storage systems seem to require allocating fixed amounts of space to them ahead of time... that is not fire and forget, is not as useful to the storage net, and is pointless. They should offer modes to dynamically use all unused space in a get out of the way of the user fashion. There's also huge potential in offering managed trees of knowledge that are deduplicated by the underlying storage net. 500M hard copies of the latest popstar collection... not useful. Curating meta layers over 1 adequately distributed copy... is.