Just as an example of how crypto can help solve some problems in this arena see VideoCoin's proof system: (https://medium.com/videocoin/proof-system-for-videocoin-stor... and https://medium.com/videocoin/proof-of-transcoding-as-a-new-c...)

They are attempting to decentralize and distribute video encode/delivery, and a big piece of that is a poof of work implementation to incentivize and reward reliable nodes.

Just one example, but there are others, and a lot of progress has been made to reduce the strain caused by throwing crypto into something that fundamentally needs to be very fast and lightweight to be usable.

Edit: Corrected duplicate links