That's according to Vitalik Buterin, founder of decentralised app Ethere?um, who discussed the problems of web middlemen at FutureFest in London last weekend.

"Migrating from one platform to another is hard and only going to get harder," he said, explaining that he's tried to shift from one email provider to another, and even runs an out-of-office auto responder, but still gets messages to the original account years later. "It's hard to switch."

And the lock-in is only going to get worse, not least as email addresses are increasingly used as identity tokens online. "By 2025 I think—if not now—it'll be harder to change the digital platforms that you're using than it'll be to change your country of residence," he said.