[dotancohen]

That brings up an interesting conundrum. If PoW were implemented, could known-valid (i.e. goodstanding for over a decade) accounts be switched over to PoS instead? Or paying accounts?

PoW could be written into infrequent pages such as the registration page and reset password page. It could run while the user fills in the form. I might implement this on some sites that get attacked.

[hedora]

This gives me an idea: thanks to anti-spam mechanisms residential proxies + headless browsers provide a better experiences than regular browsing on real devices.

Instead of PoW, maybe just make the clients prove they are capable of proxying browser sessions?

[dotancohen]

We're not far from having VPN robots intercept our browsing, solve the captchas, close all the popups, remove all the ads, reformat the page to be comfortable to read, and send it over the airwaves using less bandwidth.

I would pay for a VPN that does this, I could imagine this being the next iteration of Opera's VPN.