Is Hashcash better, achieving the same goal with less user involvement?
We’re not proposing to eliminate Hashcash. Any viable solution to spam will likely draw on myriad techniques. That said, we believe CentMail is intrinsically more socially efficient in the sense that nothing (e.g., CPU cycles) is wasted. • Don’t micropayments exert a large cognitive cost on users? Using CentMail does not require making a decision every time you send an email about whether or not to donate a penny. In contrast, users make upfront donations (typically $5-$10) that often amount to enough stamps to last several months or even years. • Will demanding too much from a sender dampen the free flow of information? Could it even be viewed as a restriction of free speech? By analogy, postage stamps on paper mail are generally not considered an infringement on free speech. More to the point, CentMail is coercion-free. Senders choose to attach stamps proving they made charitable donations and recipients choose to read those messages based on any criteria they like, including potenti
