In reply to Charles Runyan.

Spammers can get past most anti-spam tools by simply throwing more computer resources at it. Things like honey pots etc. can be bypassed by just rendering the entire page in a browser for example (in an automated fashion), but this requires significant amounts of computing power, which actually adds up to a significant amount of cash to power their servers. Simply hammering a site with post requests is cheap, having to render the entire page each time is expensive.

The system mentioned above takes that a step further, by forcing the spammer to not only render the page, but do a crap-ton of computer processing on top of that. The cost to do the calculation should hopefully cost more than any spammer is willing to pay, or at least it'll get to the point where it's cheaper to pay a human to do the spamming.

I've seen lots of people claiming that humans "must be spamming me" because their existing anti-spam solutions failed to stop them. I have never actually seen a case of this myself though. It's always been a case of the spammer simply throwing more computing resources at the problem. This plugin can hopefully push the cost to high for the spammers to bear.

The way it could make money, is by doing useful calculations. Things like cracking hashes for Bitcoins for example is a simple way to generate money on the fly and if you can offload that onto the browser/CPU of someone who is attempting to log into your site, then you could generate a little bit of money each time.