Re:Show HN: Replace CAPTCHA with Proof-of-Work
by bitJericho on Wednesday June 25, 2014 @01:39PM
(#7945517)
Good point. In a closed community, you could ask users to wait 60 seconds to register/login/etc, or they could pay 10 bucks a year for instant access all the time (plus perks since most people wouldn't care about the wait once in a while).
This could be used by those downloader sites that make users wait.
There's still an opportunity cost. Would they prefer to hit a service which limits their machines to a few thousand attempts per day, or a service which does not and lets them put through several million attempts per day?
> Even I don't pay for CPU load on my VPS.
Perhaps not, but it sets a hard limit on how much you can do in a given time period.
> That's really expensive because it's real money.
If they're stealing computer time via a botnet, they're probably not going to be paying Amazon Turk with their own credit card.