Hi. I've run into an interesting article to use proof-of-work instead of captcha to twart spammers.
To make it too expensive for spammers. Maybe something to consider for Fossile in the future?

PS: I originally wanted to post on AltHttpd, but Captchas are more Fossile related I think

• Don't spammers often use botnets/hijacked computers to send their messages, in which case it would be someone else's energy wasted?
• Fossil's captcha is only used to create an account (or login as anonymous). Once they're in, someone can make unlimited forum posts (or whatever the permissions allow). So, proof of work wouldn't really make it more expensive to spam a fossil site, unless the proof was so significant that it also annoyed legitimate users.
• I'm morally opposed to schemes that encourage wasting energy. That includes crypto currencies.