RE: DTube - Where is the data stored ?
DTube uses IPFS (the Interplanetary File System) which stores the files in little bits scattered across the internet (encrypted). Then when called it finds the pieces of the video and pulls them all in to reassemble them. I ran a "go" server to host files but it was pretty disk intensive.
Popular content loads really quick, but less called videos are slow.
IPFS is a really good idea and several sites use it. A bit slow for playback.