From @lgierth on Sat Jan 30 2016 22:52:37 GMT+0000 (UTC)
Permanence != Persistance
Permanence is about naming: content-addressing makes it so that an object’s name will always be the same. The “permanent web” is a web of links between objects with permanent names. The names are always the same, and thus the links won’t break.
Persistance is about storage: IPFS itself currently handles this by means of “pinning”, which excludes an object and its children from garbage collection within one IPFS node. In the future there will be more involved ways of managing persistance. One of them is Filecoin (paper), and there a couple of concrete ideas for an ipfs-cluster tool (ipfs/notes#58).