P2P everything, then. To scale up to a billion+ users of [whatever], it's easier if every user controls their own data (and some of 'nearby' users) on their ow

P2P everything, then. To scale up to a billion+ users of [whatever], it's easier if every user controls their own data (and some of 'nearby' users) on their own devices. Logically you'd need P2P between those billion+ users to make that network as a whole work. BUT: figuring out how to do that well, is hard. Doing that in centralized manner (centralized database, users are clients only, etc) is easier. And gives maximum control to whoever starts it. Of course scaling that means big hosting / bandwidth costs, to recoup (and profit!), enter advertising & all the bad incentives that come with it. Like you, I hope the ad-supported everything crap is just a transitional stage, and by-the-people, for-the-people becomes the norm. But P2P services done well is hard. The struggles of crypto coins, (truly) decentralized file sharing, and would-be FB competitors are just a few examples.