Something I always like to figure out in any decentralized system is where it is stored. Here it is stored on a blockchain. (yay) But where is this actually s

Something I always like to figure out in any decentralized system is where it is stored. Here it is stored on a blockchain. (yay) But where is this actually stored? Is it expected that N users will store it for everyone else? Will everyone have a copy of the entire thing? If this were to become popular I presume it would grow pretty big.