Plex is a great media server solution with clients for Windows, Mac, iOS, Android and may others. They have MacOS, Linux and Windows server’s installations but not everyone wants to have their own sever so Plex are launching something called Plex Cloud.
Plex Cloud is a Plex Media Server stored in the cloud using Amazon Drive. You don’t need to have a NAS or server with all your media is stored in Amazon’s cloud. Currently Plex Cloud is in private beta which you can sign up to join here with Plex Pass holders being given priority.
The initial rollout is with Amazon’s cloud but Plex are evaluating other cloud providers, I would love to see OneDrive as I have 1TB of storage there.
Read more about it on the Plex blog and you can signup for the beta here