Surprised there are comments about essentially trivial network-layer implementation details, and not so much about culture and UX.

As an alternative:

- Private and federated. Everyone has a personal server application which spans multiple personal computing, storage, and peripheral devices and supports federated access at varying levels of security.

- The server stores and manages a user's private data and anything else they feel like storing or sharing. (This requires unobtanium level security, but since we're imagining let's pretend this is a solved problem and see where it takes us.)

- Sharing of all kinds is user controlled and is opt-in across multiple competing federated networks. This includes social networks - with the difference that anyone can start their own network, for any purpose.

- Networks are decentralised and peer-to-peer, and do not store personal data, track, or profile users. This is a user=centric network where users own and control their data. Not an industrial data silo network.

- Users can share different interest profiles and personal details across different networks with varying levels of security and implied credibility.

- Ads are opt=in not opt-out, and defined by voluntary and informed profile and interest sharing, not involuntary and uninformed data harvesting.

- Anonymous microtransactions are a thing. Anyone can sell at scale with as little friction as possible.

- There are no cryptocurrencies and no blockchain tech, because generating random numbers with the equivalent of your own electrical substation is fucking stupid. There is a low-energy secure equivalent. (See unobtanium. Or is it?)

- A common kit of essential server apps is open sourced and community-maintained.

- Commercial and/or professional apps are available by hire or subscription. Servers have a multi-profile multi-layer security model which controls which layer of personal and/or server data outsider apps have access to.

- All paid-for apps supply full details of the schemas and file formats they use, to guarantee that users can freely transfer data to a competing app provider so apps and services hold personal data hostage and have to compete on service quality, not on retention gaming.

- Hacking, malware, virus creation, phishing, and so on, are punished by deletion of personal server data and reduction to the most basic server hardware and software. For serious and repeat offenders, this is for life.

- IoT devices are treated as personal server peripherals with no external data sharing (except by opt-in.)

- Government and military networks use an expanded version of the same system. Municipal, military, and internal gov services run on separate private subnetworks which can only be accessed through authorised devices with extra ID verification, not through general public logins.

Basically it's a combination of device security, private ID (probably biometric), sacrosanct personal data protection, high user-controlled privacy, super low cost of entry for entrepreneurial service provision, squashing of local, national and international scales, and strong forcing of anti-monopolistic competition - the opposite of the current model, which seems to be about herding users into virtual pens owned by monopolists, applying various psychological patterns to control and trigger behaviour, monitoring behaviour and sentiment through minimal privacy, and having to deal with very leaky and insecure devices and systems.