Say, you have a website that is being DDOSed. Instead of CAPTCHA, you can put a script on it to mine some Yescrypt coin (CPU-only) shares before opening access to the site (or do other things needing spam protection). Of course, you can adjust difficulty depending on DDOS volume and your greed.
For a normal user this will take a few seconds on an average PC. No more annoying CAPTCHAs, just wait a bit. For a DDOSer this will be a pain. Moreover, DDOSer will have to mine coins for you! DDOS will give profits to website owners, with no more paid subscription to Cloudfare.
If someone codes up the necessary libraries and end-user utilities, I would be very keen to use it on the forum
This is a bounty! What CPU-mineable altcoin will be mined as proof-of-work to log in to this forum? We need: 1. Javascript client-side miner for CPU-only algos. This depends mostly on coins' developers and communities. 2. Server-side scripts. This depends on server-side software. I am not professional coder so it depends on you!