[woah]

> Could a miner save on bandwidth costs by just hoarding a bunch of data, but never serving it up? I guess that they must have a solution for that, but is the solution decentralized?

I've always suspected this will be the case with Filecoin. Whether or not it is profitable depends on the ratio between storage and bandwidth costs. If you can store stuff cheaply but your bandwidth is expensive, then it make sense to store junk data if your hard drives are not full.

Filecoin really has two incentive mechanisms: A proof-of-storage-hardware mining scheme similar to proof of work which does not preclude storing useful data, along with a retrieval market which should make storing useful data more profitable than not in most cases.