Hashcash does not aim to prevent spam from happening; but to make it more expensive to generate. Increasing production costs may well be the most direct way of making spam less profitable, but it is not the only way to do so. Decreasing expected returns may prove more practical.

Once again, it is not Google-the-corporation that solely benefits from nofollow. Advertisers who rely on spam ("SEO") are harmed by it. People who use Google (and like I said, other search engines that use inbound links for ranking) benefit from it. Last I checked, there were a few of those. Of the people you correspond with, how many use hashcash? (For me, the figure changes drastically if I count mail I send to myself. But hey, I'm optimistic.)

Comment spam is worth more for the spammer if it influences rankings. Make that: the fact that comment spam can influence rankings is valuable for spammers. This is qualitatively different from email spam, where the recipient either responds with a purchase or doesn't. If a spammer can top the search engine rankings, he expects much bigger bucks than those he'd get from just N more recipients.

Perhaps this problem was created by Google like one of your cited articles claims. Could be, and immaterial. This is everybody's problem now, and everybody stands to gain if it is mitigated.

In reply to Re^5: (OT) nofollow considered harmful by gaal
in thread CPAN::Forum opens its virtual doors by szabgab

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