How is the network infrastructure built for manufacturers

Networks are places with online services for personal accounts that are signed up.
These networks has unlimited space for IDs, think of it as a infinite world full of IDs floating around filled with online information in each personal ID, there are millions and millions of personal accounts in the online networks. Each of the networks are dedicated, every manufacturer (Microsoft, Sony, Nintendo, Apple ;etc) has its own dedicated online network. Every network has a certain infrastructure of online services but the storage for IDs and data inside the IDs is unlimited and same kind of storage for every network. Each ID for networks are personal and shouldn't be shared, even by just two people.